From 32e7ac4461e51adb82638db299c4c787bf90b4dd Mon Sep 17 00:00:00 2001
From: jmcollin <jean-marie.collin@prestashop.com>
Date: Sun, 31 May 2026 17:28:41 +0200
Subject: [PATCH] feat(renderer): emit CommonMark-compliant XHTML output

Block elements now trail \n, containers have internal newlines, void elements use self-closing syntax (<hr />, <br />, <img />).
---
 src/Renderer/HtmlRenderer.php                 |  31 ++--
 tests/Integration/MarkdownParserTest.php      |  60 +++----
 tests/Integration/fixtures/blockquotes.html   |   7 +-
 tests/Integration/fixtures/code-blocks.html   |   3 +-
 tests/Integration/fixtures/columns-xss.html   |   4 +-
 tests/Integration/fixtures/columns.html       |  10 +-
 tests/Integration/fixtures/emphasis.html      |   5 +-
 .../fixtures/hard-line-breaks.html            |  11 +-
 tests/Integration/fixtures/headings.html      |   7 +-
 tests/Integration/fixtures/links-images.html  |   4 +-
 tests/Integration/fixtures/lists.html         |  11 +-
 tests/Integration/fixtures/mixed.html         |  12 +-
 .../fixtures/nested-blockquotes.html          |   8 +-
 .../Integration/fixtures/reference-links.html |   7 +-
 .../Integration/fixtures/setext-headings.html |   9 +-
 tests/Integration/fixtures/strikethrough.html |   6 +-
 tests/Integration/fixtures/xss-injection.html |   4 +-
 tests/Unit/AutolinkTest.php                   |   8 +-
 tests/Unit/ColumnsRendererTest.php            |   2 +-
 tests/Unit/EmphasisDelimiterStackTest.php     |   2 +-
 tests/Unit/FencedCodeTildeTest.php            |  28 ++--
 tests/Unit/FootnoteTest.php                   |  41 ++---
 tests/Unit/IndentedCodeBlockTest.php          |  10 +-
 tests/Unit/LinkAngleBracketUrlTest.php        |  14 +-
 tests/Unit/LinkRefAngleBracketUrlTest.php     |  20 +--
 tests/Unit/LinkRefTitleVariantsTest.php       |  18 +--
 tests/Unit/LinkTitleVariantsTest.php          |  20 +--
 tests/Unit/LooseTightListTest.php             |  26 +--
 tests/Unit/Renderer/XhtmlOutputFormatTest.php | 153 ++++++++++++++++++
 tests/Unit/RendererEntityTest.php             |   8 +-
 tests/Unit/RendererTest.php                   |  62 +++----
 tests/Unit/SetextHeadingMultilineTest.php     |   2 +-
 32 files changed, 424 insertions(+), 189 deletions(-)
 create mode 100644 tests/Unit/Renderer/XhtmlOutputFormatTest.php

diff --git a/src/Renderer/HtmlRenderer.php b/src/Renderer/HtmlRenderer.php
index 9b1717d..aa832bb 100644
--- a/src/Renderer/HtmlRenderer.php
+++ b/src/Renderer/HtmlRenderer.php
@@ -62,20 +62,20 @@ private function renderNode(NodeInterface $node): string
     {
         return match (true) {
             $node instanceof HeadingNode      => $this->renderHeading($node),
-            $node instanceof ParagraphNode    => '<p>' . $this->renderChildren($node->children) . '</p>',
-            $node instanceof BlockquoteNode   => '<blockquote>' . $this->renderChildren($node->children) . '</blockquote>',
+            $node instanceof ParagraphNode    => '<p>' . $this->renderChildren($node->children) . "</p>\n",
+            $node instanceof BlockquoteNode   => "<blockquote>\n" . $this->renderChildren($node->children) . "</blockquote>\n",
             $node instanceof ListNode         => $this->renderList($node),
             $node instanceof ListItemNode     => $this->renderListItem($node),
             $node instanceof FencedCodeNode   => $this->renderFencedCode($node),
-            $node instanceof IndentedCodeNode => '<pre><code>' . $this->esc($node->content) . '</code></pre>',
-            $node instanceof HorizontalRuleNode => '<hr>',
+            $node instanceof IndentedCodeNode => '<pre><code>' . $this->esc($node->content) . "</code></pre>\n",
+            $node instanceof HorizontalRuleNode => "<hr />\n",
             $node instanceof ColumnsNode       => $this->renderColumns($node),
             // Raw HTML blocks: sanitize if allowRawHtml, else escape (XSS-safe default).
             $node instanceof RawHtmlBlockNode =>
                 $this->allowRawHtml
-                    ? $this->sanitizer->sanitize($node->content)
-                    : $this->esc($node->content),
-            $node instanceof HardBreakNode    => '<br>',
+                    ? $this->sanitizer->sanitize($node->content) . "\n"
+                    : $this->esc($node->content) . "\n",
+            $node instanceof HardBreakNode    => "<br />\n",
             // HTML entities pass through verbatim — validated by InlineParser, no esc() needed.
             $node instanceof HtmlEntityNode   => $node->entity,
             $node instanceof TextNode         => $this->esc($node->text),
@@ -112,7 +112,7 @@ private function renderChildren(array $nodes): string
     private function renderHeading(HeadingNode $node): string
     {
         $tag = 'h' . $node->level;
-        return '<' . $tag . '>' . $this->renderChildren($node->children) . '</' . $tag . '>';
+        return '<' . $tag . '>' . $this->renderChildren($node->children) . '</' . $tag . ">\n";
     }
 
     private function renderList(ListNode $node): string
@@ -122,7 +122,7 @@ private function renderList(ListNode $node): string
         foreach ($node->children as $item) {
             $inner .= $this->renderListItem($item, $node->loose);
         }
-        return '<' . $tag . '>' . $inner . '</' . $tag . '>';
+        return '<' . $tag . ">\n" . $inner . '</' . $tag . ">\n";
     }
 
     private function renderListItem(ListItemNode $node, bool $loose = false): string
@@ -130,10 +130,13 @@ private function renderListItem(ListItemNode $node, bool $loose = false): string
         $content = $this->renderListItemContent($node->children, $loose);
 
         if ($node->checked === null) {
-            return '<li>' . $content . '</li>';
+            if ($loose) {
+                return "<li>\n" . $content . "</li>\n";
+            }
+            return '<li>' . $content . "</li>\n";
         }
         $checkbox = '<input type="checkbox" disabled' . ($node->checked ? ' checked' : '') . '>';
-        return '<li>' . $checkbox . ' ' . $content . '</li>';
+        return '<li>' . $checkbox . ' ' . $content . "</li>\n";
     }
 
     /**
@@ -161,7 +164,7 @@ private function renderListItemContent(array $children, bool $loose): string
 
         $html = '';
         if ($inlinePart !== []) {
-            $html .= '<p>' . $this->renderChildren($inlinePart) . '</p>';
+            $html .= '<p>' . $this->renderChildren($inlinePart) . "</p>\n";
         }
         foreach ($blockPart as $block) {
             $html .= $this->renderNode($block);
@@ -187,7 +190,7 @@ private function renderFencedCode(FencedCodeNode $node): string
         $classAttr = ($lang ?? '') !== ''
             ? ' class="' . $this->esc('language-' . (string) $lang) . '"'
             : '';
-        return '<pre><code' . $classAttr . '>' . $this->esc($node->content) . '</code></pre>';
+        return '<pre><code' . $classAttr . '>' . $this->esc($node->content) . "</code></pre>\n";
     }
 
     private function renderLink(LinkNode $node): string
@@ -205,7 +208,7 @@ private function renderImage(ImageNode $node): string
         $titleAttr = $node->title !== null
             ? ' title="' . $this->esc($node->title) . '"'
             : '';
-        return '<img src="' . $this->esc($node->src) . '" alt="' . $this->esc($node->alt) . '"' . $titleAttr . '>';
+        return '<img src="' . $this->esc($node->src) . '" alt="' . $this->esc($node->alt) . '"' . $titleAttr . ' />';
     }
 
     private function renderAutolink(AutolinkNode $node): string
diff --git a/tests/Integration/MarkdownParserTest.php b/tests/Integration/MarkdownParserTest.php
index 7f0cf96..8070614 100644
--- a/tests/Integration/MarkdownParserTest.php
+++ b/tests/Integration/MarkdownParserTest.php
@@ -74,7 +74,7 @@ public function testFullDocumentPipeline(): void
         $this->assertStringContainsString('<strong>bold</strong>', $html);
         $this->assertMatchesRegularExpression('/<ul>\s*<li>item<\/li>\s*<\/ul>/', $html);
         $this->assertStringContainsString('<blockquote>', $html);
-        $this->assertStringContainsString('<hr>', $html);
+        $this->assertStringContainsString('<hr />', $html);
     }
 
     // ── Guard: input validation ───────────────────────────────────────────────
@@ -238,7 +238,7 @@ public function testSimpleNestedList(): void
         $md = "- a\n  - b\n  - c\n- d";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<ul><li>a<ul><li>b</li><li>c</li></ul></li><li>d</li></ul>', $html);
+        $this->assertSame("<ul>\n<li>a<ul>\n<li>b</li>\n<li>c</li>\n</ul>\n</li>\n<li>d</li>\n</ul>\n", $html);
     }
 
     public function testThreeLevelNesting(): void
@@ -246,7 +246,7 @@ public function testThreeLevelNesting(): void
         $md = "- a\n  - b\n    - c";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<ul><li>a<ul><li>b<ul><li>c</li></ul></li></ul></li></ul>', $html);
+        $this->assertSame("<ul>\n<li>a<ul>\n<li>b<ul>\n<li>c</li>\n</ul>\n</li>\n</ul>\n</li>\n</ul>\n", $html);
     }
 
     public function testMixedNestingTypes(): void
@@ -254,7 +254,7 @@ public function testMixedNestingTypes(): void
         $md = "1. first\n   - nested\n2. second";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<ol><li>first<ul><li>nested</li></ul></li><li>second</li></ol>', $html);
+        $this->assertSame("<ol>\n<li>first<ul>\n<li>nested</li>\n</ul>\n</li>\n<li>second</li>\n</ol>\n", $html);
     }
 
     public function testFlatListUnchanged(): void
@@ -262,7 +262,7 @@ public function testFlatListUnchanged(): void
         $md = "- a\n- b\n- c";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<ul><li>a</li><li>b</li><li>c</li></ul>', $html);
+        $this->assertSame("<ul>\n<li>a</li>\n<li>b</li>\n<li>c</li>\n</ul>\n", $html);
     }
 
     public function testInlineContentInNestedItem(): void
@@ -271,7 +271,7 @@ public function testInlineContentInNestedItem(): void
         $html = $this->parser->parse($md);
 
         $this->assertSame(
-            '<ul><li><strong>bold</strong><ul><li><em>em</em></li></ul></li></ul>',
+            "<ul>\n<li><strong>bold</strong><ul>\n<li><em>em</em></li>\n</ul>\n</li>\n</ul>\n",
             $html
         );
     }
@@ -282,7 +282,7 @@ public function testLargeDepthGapCollapsesToDirectNesting(): void
         $md = "- top\n" . str_repeat(' ', 20) . "- deep";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<ul><li>top<ul><li>deep</li></ul></li></ul>', $html);
+        $this->assertSame("<ul>\n<li>top<ul>\n<li>deep</li>\n</ul>\n</li>\n</ul>\n", $html);
     }
 
     public function testUlFollowedByOlAtSameDepthProducesTwoSeparateLists(): void
@@ -292,7 +292,7 @@ public function testUlFollowedByOlAtSameDepthProducesTwoSeparateLists(): void
         $md = "- ul item\n1. ol item";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<ul><li>ul item</li></ul><ol><li>ol item</li></ol>', $html);
+        $this->assertSame("<ul>\n<li>ul item</li>\n</ul>\n<ol>\n<li>ol item</li>\n</ol>\n", $html);
     }
 
     public function testDepthCapAt32DoesNotCrashAndProducesTwoLists(): void
@@ -325,7 +325,7 @@ public function testNestedBlockquoteMixedLevels(): void
         $html = $this->parser->parse($md);
 
         $this->assertSame(
-            '<blockquote><p>outer</p><blockquote><p>inner</p></blockquote><p>outer again</p></blockquote>',
+            "<blockquote>\n<p>outer</p>\n<blockquote>\n<p>inner</p>\n</blockquote>\n<p>outer again</p>\n</blockquote>\n",
             $html,
         );
     }
@@ -336,7 +336,7 @@ public function testThreeLevelBlockquote(): void
         $html = $this->parser->parse($md);
 
         $this->assertSame(
-            '<blockquote><blockquote><blockquote><p>triple</p></blockquote></blockquote></blockquote>',
+            "<blockquote>\n<blockquote>\n<blockquote>\n<p>triple</p>\n</blockquote>\n</blockquote>\n</blockquote>\n",
             $html,
         );
     }
@@ -347,7 +347,7 @@ public function testLevelDecreaseThenIncrease(): void
         $html = $this->parser->parse($md);
 
         $this->assertSame(
-            '<blockquote><p>a</p><blockquote><p>b</p></blockquote><p>c</p><blockquote><p>d</p></blockquote></blockquote>',
+            "<blockquote>\n<p>a</p>\n<blockquote>\n<p>b</p>\n</blockquote>\n<p>c</p>\n<blockquote>\n<p>d</p>\n</blockquote>\n</blockquote>\n",
             $html,
         );
     }
@@ -379,7 +379,7 @@ public function testMultiLineSameLevelJoinedWithSpace(): void
         $md = "> line one\n> line two";
         $html = $this->parser->parse($md);
 
-        $this->assertSame('<blockquote><p>line one line two</p></blockquote>', $html);
+        $this->assertSame("<blockquote>\n<p>line one line two</p>\n</blockquote>\n", $html);
     }
 
     public function testLevelSkipOneToThree(): void
@@ -389,7 +389,7 @@ public function testLevelSkipOneToThree(): void
         $html = $this->parser->parse($md);
 
         $this->assertSame(
-            '<blockquote><p>a</p><blockquote><blockquote><p>c</p></blockquote></blockquote></blockquote>',
+            "<blockquote>\n<p>a</p>\n<blockquote>\n<blockquote>\n<p>c</p>\n</blockquote>\n</blockquote>\n</blockquote>\n",
             $html,
         );
     }
@@ -401,7 +401,7 @@ public function testBlockquoteAdjacentToParagraph(): void
         $html = $this->parser->parse($md);
 
         $this->assertSame(
-            '<blockquote><p>quoted</p></blockquote><p>plain paragraph</p>',
+            "<blockquote>\n<p>quoted</p>\n</blockquote>\n<p>plain paragraph</p>\n",
             $html,
         );
     }
@@ -416,7 +416,7 @@ public function testBlankLineBetweenBlockquoteLevelsSeparatesNodes(): void
 
         // Two separate top-level blockquotes (blank line resets context).
         $this->assertSame(
-            '<blockquote><p>first</p></blockquote><blockquote><p>second</p></blockquote>',
+            "<blockquote>\n<p>first</p>\n</blockquote>\n<blockquote>\n<p>second</p>\n</blockquote>\n",
             $html,
         );
     }
@@ -426,13 +426,13 @@ public function testBlankLineBetweenBlockquoteLevelsSeparatesNodes(): void
     public function testCheckedTaskItemRendersCheckbox(): void
     {
         $html = $this->parser->parse('- [x] Done');
-        $this->assertSame('<ul><li><input type="checkbox" disabled checked> Done</li></ul>', $html);
+        $this->assertSame("<ul>\n<li><input type=\"checkbox\" disabled checked> Done</li>\n</ul>\n", $html);
     }
 
     public function testUncheckedTaskItemRendersCheckbox(): void
     {
         $html = $this->parser->parse('- [ ] Todo');
-        $this->assertSame('<ul><li><input type="checkbox" disabled> Todo</li></ul>', $html);
+        $this->assertSame("<ul>\n<li><input type=\"checkbox\" disabled> Todo</li>\n</ul>\n", $html);
     }
 
     public function testMixedTaskList(): void
@@ -481,49 +481,49 @@ public function testTwoTrailingSpacesProducesBr(): void
     {
         // Two trailing spaces before \n must become <br> not a space.
         $html = $this->parser->parse("foo  \nbar");
-        $this->assertSame('<p>foo<br>bar</p>', $html);
+        $this->assertSame("<p>foo<br />\nbar</p>\n", $html);
     }
 
     public function testBackslashLineBreakProducesBr(): void
     {
         // Trailing backslash before \n must become <br>.
         $html = $this->parser->parse("foo\\\nbar");
-        $this->assertSame('<p>foo<br>bar</p>', $html);
+        $this->assertSame("<p>foo<br />\nbar</p>\n", $html);
     }
 
     public function testNoTrailingSpacesProducesSoftBreak(): void
     {
         // Without trailing spaces the lines are soft-joined with a space.
         $html = $this->parser->parse("foo\nbar");
-        $this->assertSame('<p>foo bar</p>', $html);
+        $this->assertSame("<p>foo bar</p>\n", $html);
     }
 
     public function testHardBreakInsideInlineContent(): void
     {
         // Hard break after inline strong element.
         $html = $this->parser->parse("**bold**  \ntext");
-        $this->assertSame('<p><strong>bold</strong><br>text</p>', $html);
+        $this->assertSame("<p><strong>bold</strong><br />\ntext</p>\n", $html);
     }
 
     public function testMultipleHardBreaksInOneParagraph(): void
     {
         // Multiple hard breaks in sequence.
         $html = $this->parser->parse("a  \nb  \nc");
-        $this->assertSame('<p>a<br>b<br>c</p>', $html);
+        $this->assertSame("<p>a<br />\nb<br />\nc</p>\n", $html);
     }
 
     public function testThreeTrailingSpacesStillOneBr(): void
     {
         // Three or more trailing spaces → still one <br>.
         $html = $this->parser->parse("foo   \nbar");
-        $this->assertSame('<p>foo<br>bar</p>', $html);
+        $this->assertSame("<p>foo<br />\nbar</p>\n", $html);
     }
 
     public function testHardBreakOnLastLineOfParagraphStripped(): void
     {
         // Hard break on last line of a paragraph → no trailing <br> (CommonMark §6.7).
         $html = $this->parser->parse("foo  ");
-        $this->assertSame('<p>foo</p>', $html);
+        $this->assertSame("<p>foo</p>\n", $html);
     }
 
     public function testDoubleBackslashIsNotHardBreak(): void
@@ -538,7 +538,7 @@ public function testHardBreakLineWithUnsafeUrlIsFiltered(): void
         // isSafeUrl() must still fire on content that carries hard_break=true.
         $html = $this->parser->parse("[click](javascript:alert(1))  \nafter");
         $this->assertStringNotContainsString('href="javascript:', $html);
-        $this->assertStringContainsString('<br>', $html);
+        $this->assertStringContainsString('<br />', $html);
     }
 
     public function testFencedCodeInnerLineWithTrailingSpacesIsNotHardBreak(): void
@@ -562,14 +562,14 @@ public function testSoftBreakBetweenParagraphLinesUnchanged(): void
     {
         // Pre-existing soft-break behavior must not regress.
         $html = $this->parser->parse("line one\nline two\nline three");
-        $this->assertSame('<p>line one line two line three</p>', $html);
+        $this->assertSame("<p>line one line two line three</p>\n", $html);
     }
 
     public function testBlankLineSeparatesParagraphs(): void
     {
         // Blank line separation of paragraphs must not regress.
         $html = $this->parser->parse("para one\n\npara two");
-        $this->assertSame('<p>para one</p><p>para two</p>', $html);
+        $this->assertSame("<p>para one</p>\n<p>para two</p>\n", $html);
     }
 
     // ── Inline HTML in headings — full pipeline (story 29) ───────────────────
@@ -620,7 +620,7 @@ public function testHardBreakIsNotMisidentifiedAsRawHtmlInline(): void
 
         // HTML output must be the canonical hard-break form.
         $html = $this->parser->parse("foo  \nbar");
-        $this->assertSame('<p>foo<br>bar</p>', $html);
+        $this->assertSame("<p>foo<br />\nbar</p>\n", $html);
 
         // AST: single ParagraphNode child.
         $this->assertCount(1, $doc->children);
@@ -655,7 +655,7 @@ public function testParseDefaultEscapesRawHtmlBlock(): void
         // Output is bare escaped text with no <p> wrapper.
         $html = $this->parser->parse('<div>raw</div>');
 
-        $this->assertSame('&lt;div&gt;raw&lt;/div&gt;', $html);
+        $this->assertSame("&lt;div&gt;raw&lt;/div&gt;\n", $html);
     }
 
     public function testParseWithAllowRawHtmlPassesThroughBlock(): void
@@ -690,6 +690,6 @@ public function testParseBackwardCompatibilityDefaultParam(): void
         // Existing callers of parse($md) still work — no exception, returns string.
         $html = $this->parser->parse('hello');
 
-        $this->assertSame('<p>hello</p>', $html);
+        $this->assertSame("<p>hello</p>\n", $html);
     }
 }
diff --git a/tests/Integration/fixtures/blockquotes.html b/tests/Integration/fixtures/blockquotes.html
index d724434..a5061b7 100644
--- a/tests/Integration/fixtures/blockquotes.html
+++ b/tests/Integration/fixtures/blockquotes.html
@@ -1 +1,6 @@
-<blockquote><p>This is a quote</p></blockquote><blockquote><p>Another quote</p></blockquote>
\ No newline at end of file
+<blockquote>
+<p>This is a quote</p>
+</blockquote>
+<blockquote>
+<p>Another quote</p>
+</blockquote>
diff --git a/tests/Integration/fixtures/code-blocks.html b/tests/Integration/fixtures/code-blocks.html
index 2df855b..985e6be 100644
--- a/tests/Integration/fixtures/code-blocks.html
+++ b/tests/Integration/fixtures/code-blocks.html
@@ -1 +1,2 @@
-<pre><code class="language-php">echo &#039;hello&#039;;</code></pre><p>Inline <code>code</code> here.</p>
\ No newline at end of file
+<pre><code class="language-php">echo &#039;hello&#039;;</code></pre>
+<p>Inline <code>code</code> here.</p>
diff --git a/tests/Integration/fixtures/columns-xss.html b/tests/Integration/fixtures/columns-xss.html
index 02fea02..685e4de 100644
--- a/tests/Integration/fixtures/columns-xss.html
+++ b/tests/Integration/fixtures/columns-xss.html
@@ -1 +1,3 @@
-<div class="grid grid-cols-2 gap-4"><div class="min-w-0"><p>&lt;script&gt;alert(1)&lt;/script&gt;</p></div><div class="min-w-0"><p>[xss](javascript:alert(1))</p></div></div>
\ No newline at end of file
+<div class="grid grid-cols-2 gap-4"><div class="min-w-0"><p>&lt;script&gt;alert(1)&lt;/script&gt;</p>
+</div><div class="min-w-0"><p>[xss](javascript:alert(1))</p>
+</div></div>
\ No newline at end of file
diff --git a/tests/Integration/fixtures/columns.html b/tests/Integration/fixtures/columns.html
index 107f347..63c0060 100644
--- a/tests/Integration/fixtures/columns.html
+++ b/tests/Integration/fixtures/columns.html
@@ -1 +1,9 @@
-<div class="grid grid-cols-2 gap-4"><div class="min-w-0"><h2>Left column</h2><p>Text with <strong>bold</strong> and <em>italic</em>.</p><ul><li>item one</li><li>item two</li></ul></div><div class="min-w-0"><h2>Right column</h2><p>A <a href="https://example.com">link</a> and <code>inline code</code>.</p></div></div>
\ No newline at end of file
+<div class="grid grid-cols-2 gap-4"><div class="min-w-0"><h2>Left column</h2>
+<p>Text with <strong>bold</strong> and <em>italic</em>.</p>
+<ul>
+<li>item one</li>
+<li>item two</li>
+</ul>
+</div><div class="min-w-0"><h2>Right column</h2>
+<p>A <a href="https://example.com">link</a> and <code>inline code</code>.</p>
+</div></div>
\ No newline at end of file
diff --git a/tests/Integration/fixtures/emphasis.html b/tests/Integration/fixtures/emphasis.html
index 866cf8f..6cb6812 100644
--- a/tests/Integration/fixtures/emphasis.html
+++ b/tests/Integration/fixtures/emphasis.html
@@ -1 +1,4 @@
-<p><strong>bold text</strong></p><p><em>italic text</em></p><p><strong>also bold</strong></p><p><em>also italic</em></p>
\ No newline at end of file
+<p><strong>bold text</strong></p>
+<p><em>italic text</em></p>
+<p><strong>also bold</strong></p>
+<p><em>also italic</em></p>
diff --git a/tests/Integration/fixtures/hard-line-breaks.html b/tests/Integration/fixtures/hard-line-breaks.html
index e0ef8fb..2c6fa4c 100644
--- a/tests/Integration/fixtures/hard-line-breaks.html
+++ b/tests/Integration/fixtures/hard-line-breaks.html
@@ -1 +1,10 @@
-<p>foo<br>bar</p><p>foo<br>bar</p><p>foo bar</p><p><strong>bold</strong><br>text</p><p>a<br>b<br>c</p>
\ No newline at end of file
+<p>foo<br />
+bar</p>
+<p>foo<br />
+bar</p>
+<p>foo bar</p>
+<p><strong>bold</strong><br />
+text</p>
+<p>a<br />
+b<br />
+c</p>
diff --git a/tests/Integration/fixtures/headings.html b/tests/Integration/fixtures/headings.html
index 51010a6..8fc41d2 100644
--- a/tests/Integration/fixtures/headings.html
+++ b/tests/Integration/fixtures/headings.html
@@ -1 +1,6 @@
-<h1>Heading 1</h1><h2>Heading 2</h2><h3>Heading 3</h3><h4>Heading 4</h4><h5>Heading 5</h5><h6>Heading 6</h6>
\ No newline at end of file
+<h1>Heading 1</h1>
+<h2>Heading 2</h2>
+<h3>Heading 3</h3>
+<h4>Heading 4</h4>
+<h5>Heading 5</h5>
+<h6>Heading 6</h6>
diff --git a/tests/Integration/fixtures/links-images.html b/tests/Integration/fixtures/links-images.html
index 7ded60f..fe23e11 100644
--- a/tests/Integration/fixtures/links-images.html
+++ b/tests/Integration/fixtures/links-images.html
@@ -1 +1,3 @@
-<p><a href="https://example.com">Visit site</a></p><p><img src="image.png" alt="alt text"></p><p><a href="https://example.com" title="My Title">With title</a></p>
\ No newline at end of file
+<p><a href="https://example.com">Visit site</a></p>
+<p><img src="image.png" alt="alt text" /></p>
+<p><a href="https://example.com" title="My Title">With title</a></p>
diff --git a/tests/Integration/fixtures/lists.html b/tests/Integration/fixtures/lists.html
index fa001f5..d83b4b8 100644
--- a/tests/Integration/fixtures/lists.html
+++ b/tests/Integration/fixtures/lists.html
@@ -1 +1,10 @@
-<ul><li>item one</li><li>item two</li><li>item three</li></ul><ol><li>first</li><li>second</li><li>third</li></ol>
\ No newline at end of file
+<ul>
+<li>item one</li>
+<li>item two</li>
+<li>item three</li>
+</ul>
+<ol>
+<li>first</li>
+<li>second</li>
+<li>third</li>
+</ol>
diff --git a/tests/Integration/fixtures/mixed.html b/tests/Integration/fixtures/mixed.html
index d22c149..3d54b88 100644
--- a/tests/Integration/fixtures/mixed.html
+++ b/tests/Integration/fixtures/mixed.html
@@ -1 +1,11 @@
-<h1>Title</h1><p>A paragraph with <strong>bold</strong> and <em>italic</em>.</p><ul><li>item 1</li><li>item 2</li></ul><blockquote><p>blockquote</p></blockquote><pre><code class="language-js">console.log(&#039;hi&#039;);</code></pre><hr>
\ No newline at end of file
+<h1>Title</h1>
+<p>A paragraph with <strong>bold</strong> and <em>italic</em>.</p>
+<ul>
+<li>item 1</li>
+<li>item 2</li>
+</ul>
+<blockquote>
+<p>blockquote</p>
+</blockquote>
+<pre><code class="language-js">console.log(&#039;hi&#039;);</code></pre>
+<hr />
diff --git a/tests/Integration/fixtures/nested-blockquotes.html b/tests/Integration/fixtures/nested-blockquotes.html
index e185b7d..4c1d948 100644
--- a/tests/Integration/fixtures/nested-blockquotes.html
+++ b/tests/Integration/fixtures/nested-blockquotes.html
@@ -1 +1,7 @@
-<blockquote><p>outer</p><blockquote><p>inner</p></blockquote><p>outer again</p></blockquote>
\ No newline at end of file
+<blockquote>
+<p>outer</p>
+<blockquote>
+<p>inner</p>
+</blockquote>
+<p>outer again</p>
+</blockquote>
diff --git a/tests/Integration/fixtures/reference-links.html b/tests/Integration/fixtures/reference-links.html
index 9e5ca0c..4f3908e 100644
--- a/tests/Integration/fixtures/reference-links.html
+++ b/tests/Integration/fixtures/reference-links.html
@@ -1 +1,6 @@
-<p><a href="https://example.com/bar" title="Bar title">foo</a></p><p><a href="https://example.com">foo</a></p><p><a href="https://example.com">foo</a></p><p><a href="https://example.com">bar</a></p><p>[foo][missing]</p><p>text</p>
\ No newline at end of file
+<p><a href="https://example.com/bar" title="Bar title">foo</a></p>
+<p><a href="https://example.com">foo</a></p>
+<p><a href="https://example.com">foo</a></p>
+<p><a href="https://example.com">bar</a></p>
+<p>[foo][missing]</p>
+<p>text</p>
diff --git a/tests/Integration/fixtures/setext-headings.html b/tests/Integration/fixtures/setext-headings.html
index 818e929..79fc138 100644
--- a/tests/Integration/fixtures/setext-headings.html
+++ b/tests/Integration/fixtures/setext-headings.html
@@ -1 +1,8 @@
-<h1>My Title</h1><h2>Sub Title</h2><h1><strong>bold</strong> title</h1><h2>text</h2><h1>Title</h1><h1>foo bar</h1><h2>line one line two line three</h2><h1><em>foo bar</em></h1>
\ No newline at end of file
+<h1>My Title</h1>
+<h2>Sub Title</h2>
+<h1><strong>bold</strong> title</h1>
+<h2>text</h2>
+<h1>Title</h1>
+<h1>foo bar</h1>
+<h2>line one line two line three</h2>
+<h1><em>foo bar</em></h1>
diff --git a/tests/Integration/fixtures/strikethrough.html b/tests/Integration/fixtures/strikethrough.html
index 4aa400e..cf099dc 100644
--- a/tests/Integration/fixtures/strikethrough.html
+++ b/tests/Integration/fixtures/strikethrough.html
@@ -1 +1,5 @@
-<p><del>foo</del></p><p><del><strong>bold</strong></del></p><p>foo <del>bar</del> baz</p><p>~~unclosed</p><p>~not~</p>
\ No newline at end of file
+<p><del>foo</del></p>
+<p><del><strong>bold</strong></del></p>
+<p>foo <del>bar</del> baz</p>
+<p>~~unclosed</p>
+<p>~not~</p>
diff --git a/tests/Integration/fixtures/xss-injection.html b/tests/Integration/fixtures/xss-injection.html
index 1089c19..2ec4fb9 100644
--- a/tests/Integration/fixtures/xss-injection.html
+++ b/tests/Integration/fixtures/xss-injection.html
@@ -1 +1,3 @@
-<p>&lt;script&gt;alert(1)&lt;/script&gt;</p><p>[xss](javascript:alert(1))</p><p>&lt;b&gt;bold attempt&lt;/b&gt;</p>
\ No newline at end of file
+<p>&lt;script&gt;alert(1)&lt;/script&gt;</p>
+<p>[xss](javascript:alert(1))</p>
+<p>&lt;b&gt;bold attempt&lt;/b&gt;</p>
diff --git a/tests/Unit/AutolinkTest.php b/tests/Unit/AutolinkTest.php
index 9141c3e..fb024c2 100644
--- a/tests/Unit/AutolinkTest.php
+++ b/tests/Unit/AutolinkTest.php
@@ -33,8 +33,8 @@ private function parse(string $input): string
         $para     = new ParagraphNode($nodes);
         $document = new DocumentNode([$para]);
         $html     = $this->renderer->render($document);
-        // Strip outer <p>...</p> to get the inner rendered content.
-        return preg_replace('/^<p>(.*)<\/p>$/s', '$1', $html) ?? $html;
+        // Strip outer <p>...</p> (and optional trailing newline) to get the inner rendered content.
+        return preg_replace('/^<p>(.*)<\/p>\n?$/s', '$1', $html) ?? $html;
     }
 
     // ── URL autolinks ─────────────────────────────────────────────────────────
@@ -238,7 +238,7 @@ public function test_url_autolink_inside_emphasis(): void
         $document = new DocumentNode([$para]);
         $html     = $this->renderer->render($document);
         $this->assertSame(
-            '<p><em><a href="https://example.com">https://example.com</a></em></p>',
+            "<p><em><a href=\"https://example.com\">https://example.com</a></em></p>\n",
             $html,
         );
     }
@@ -314,7 +314,7 @@ public function test_autolink_at_paragraph_end(): void
         $para     = new ParagraphNode($nodes);
         $document = new DocumentNode([$para]);
         $html     = $this->renderer->render($document);
-        $this->assertStringEndsWith('</a></p>', $html);
+        $this->assertStringEndsWith("</a></p>\n", $html);
     }
 
     public function test_url_autolink_very_long_url(): void
diff --git a/tests/Unit/ColumnsRendererTest.php b/tests/Unit/ColumnsRendererTest.php
index 6e71033..ef4d95c 100644
--- a/tests/Unit/ColumnsRendererTest.php
+++ b/tests/Unit/ColumnsRendererTest.php
@@ -48,7 +48,7 @@ public function testBasicTwoColumnHtmlStructure(): void
         $out = $this->renderMarkdown(":::columns\nGauche\n|||\nDroite\n:::");
 
         $this->assertSame(
-            '<div class="grid grid-cols-2 gap-4"><div class="min-w-0"><p>Gauche</p></div><div class="min-w-0"><p>Droite</p></div></div>',
+            '<div class="grid grid-cols-2 gap-4"><div class="min-w-0"><p>Gauche</p>' . "\n" . '</div><div class="min-w-0"><p>Droite</p>' . "\n" . '</div></div>',
             $out,
         );
     }
diff --git a/tests/Unit/EmphasisDelimiterStackTest.php b/tests/Unit/EmphasisDelimiterStackTest.php
index e615b93..e737fd5 100644
--- a/tests/Unit/EmphasisDelimiterStackTest.php
+++ b/tests/Unit/EmphasisDelimiterStackTest.php
@@ -36,7 +36,7 @@ private function parse(string $input): string
         $para     = new ParagraphNode($nodes);
         $document = new DocumentNode([$para]);
         $html     = $this->renderer->render($document);
-        return preg_replace('/^<p>(.*)<\/p>$/s', '$1', $html) ?? $html;
+        return preg_replace('/^<p>(.*)<\/p>\n?$/s', '$1', $html) ?? $html;
     }
 
     // ── Basic emphasis and strong ─────────────────────────────────────────────
diff --git a/tests/Unit/FencedCodeTildeTest.php b/tests/Unit/FencedCodeTildeTest.php
index c467f5b..8b8ca78 100644
--- a/tests/Unit/FencedCodeTildeTest.php
+++ b/tests/Unit/FencedCodeTildeTest.php
@@ -44,7 +44,7 @@ public function testTC01BasicTildeFenceNoInfoString(): void
     {
         $html = $this->render("~~~\nfoo\n~~~");
 
-        $this->assertSame('<pre><code>foo</code></pre>', $html);
+        $this->assertSame("<pre><code>foo</code></pre>\n", $html);
     }
 
     /**
@@ -54,7 +54,7 @@ public function testTC02TildeFenceWithInfoString(): void
     {
         $html = $this->render("~~~php\necho 1;\n~~~");
 
-        $this->assertSame('<pre><code class="language-php">echo 1;</code></pre>', $html);
+        $this->assertSame("<pre><code class=\"language-php\">echo 1;</code></pre>\n", $html);
     }
 
     /**
@@ -64,7 +64,7 @@ public function testTC03FourTildeCloseThreeTildeOpen(): void
     {
         $html = $this->render("~~~\nfoo\n~~~~");
 
-        $this->assertSame('<pre><code>foo</code></pre>', $html);
+        $this->assertSame("<pre><code>foo</code></pre>\n", $html);
     }
 
     /**
@@ -75,7 +75,7 @@ public function testTC04ThreeTildeCannotCloseFourTildeOpen(): void
         // The ~~~ line inside is treated as content, block is unclosed at EOF.
         $html = $this->render("~~~~\nfoo\n~~~\nbar");
 
-        $this->assertSame("<pre><code>foo\n~~~\nbar</code></pre>", $html);
+        $this->assertSame("<pre><code>foo\n~~~\nbar</code></pre>\n", $html);
     }
 
     /**
@@ -85,7 +85,7 @@ public function testTC05BacktickLineIsContentInsideTildeFence(): void
     {
         $html = $this->render("~~~\nfoo\n```\n~~~");
 
-        $this->assertSame("<pre><code>foo\n```</code></pre>", $html);
+        $this->assertSame("<pre><code>foo\n```</code></pre>\n", $html);
     }
 
     /**
@@ -95,7 +95,7 @@ public function testTC06TildeLineIsContentInsideBacktickFence(): void
     {
         $html = $this->render("```\nfoo\n~~~\n```");
 
-        $this->assertSame("<pre><code>foo\n~~~</code></pre>", $html);
+        $this->assertSame("<pre><code>foo\n~~~</code></pre>\n", $html);
     }
 
     /**
@@ -105,7 +105,7 @@ public function testTC07ThreeSpaceIndentOnFenceLines(): void
     {
         $html = $this->render("   ~~~\nfoo\n   ~~~");
 
-        $this->assertSame('<pre><code>foo</code></pre>', $html);
+        $this->assertSame("<pre><code>foo</code></pre>\n", $html);
     }
 
     /**
@@ -116,7 +116,7 @@ public function testTC08FourSpaceIndentProducesIndentedCodeBlock(): void
         // "    ~~~" is an indented code block containing "~~~" as content.
         $html = $this->render("    ~~~\n");
 
-        $this->assertSame("<pre><code>~~~\n</code></pre>", $html);
+        $this->assertSame("<pre><code>~~~\n</code></pre>\n", $html);
         $this->assertStringNotContainsString('</code></pre><pre><code>', $html);
     }
 
@@ -127,7 +127,7 @@ public function testTC09UnclosedTildeFenceEmittedAtEof(): void
     {
         $html = $this->render("~~~\nfoo\nbar");
 
-        $this->assertSame("<pre><code>foo\nbar</code></pre>", $html);
+        $this->assertSame("<pre><code>foo\nbar</code></pre>\n", $html);
     }
 
     /**
@@ -137,7 +137,7 @@ public function testTC10FourTildeOpenClosedByFourTildeClose(): void
     {
         $html = $this->render("~~~~\nfoo\n~~~~");
 
-        $this->assertSame('<pre><code>foo</code></pre>', $html);
+        $this->assertSame("<pre><code>foo</code></pre>\n", $html);
     }
 
     /**
@@ -148,7 +148,7 @@ public function testTC11HtmlCharactersEscaped(): void
         $html = $this->render("~~~\n<b>bold</b> & \"quotes\"\n~~~");
 
         $this->assertSame(
-            '<pre><code>&lt;b&gt;bold&lt;/b&gt; &amp; &quot;quotes&quot;</code></pre>',
+            "<pre><code>&lt;b&gt;bold&lt;/b&gt; &amp; &quot;quotes&quot;</code></pre>\n",
             $html,
         );
     }
@@ -162,7 +162,7 @@ public function testTC12BacktickInTildeInfoStringStrippedByRenderer(): void
         // Info string is a single backtick; after renderer sanitisation it becomes ''.
         $html = $this->render("~~~ `\nconsole.log(1);\n~~~");
 
-        $this->assertSame('<pre><code>console.log(1);</code></pre>', $html);
+        $this->assertSame("<pre><code>console.log(1);</code></pre>\n", $html);
     }
 
     /**
@@ -184,7 +184,7 @@ public function testTC14AdjacentBacktickThenTildeFence(): void
         $html = $this->render("```\nhello\n```\n~~~\nworld\n~~~");
 
         $this->assertSame(
-            '<pre><code>hello</code></pre><pre><code>world</code></pre>',
+            "<pre><code>hello</code></pre>\n<pre><code>world</code></pre>\n",
             $html,
         );
     }
@@ -197,7 +197,7 @@ public function testTC15ParagraphBeforeTildeFence(): void
         $html = $this->render("paragraph text\n\n~~~\ncode\n~~~");
 
         $this->assertSame(
-            '<p>paragraph text</p><pre><code>code</code></pre>',
+            "<p>paragraph text</p>\n<pre><code>code</code></pre>\n",
             $html,
         );
     }
diff --git a/tests/Unit/FootnoteTest.php b/tests/Unit/FootnoteTest.php
index 632305e..9db4f93 100644
--- a/tests/Unit/FootnoteTest.php
+++ b/tests/Unit/FootnoteTest.php
@@ -52,7 +52,7 @@ public function testBasicReferenceAndDefinition(): void
         $md = "Text[^1].\n\n[^1]: First footnote.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Text<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
+            "<p>Text<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">First footnote. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -68,7 +68,7 @@ public function testAppearanceOrderNumbering(): void
         $md = "Alpha[^b] and Beta[^a].\n\n[^a]: Definition A.\n[^b]: Definition B.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Alpha<sup><a href="#fn-1" id="fnref-1">1</a></sup> and Beta<sup><a href="#fn-2" id="fnref-2">2</a></sup>.</p>'
+            "<p>Alpha<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup> and Beta<sup><a href=\"#fn-2\" id=\"fnref-2\">2</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Definition B. <a href="#fnref-1">↩</a></li>'
             . '<li id="fn-2">Definition A. <a href="#fnref-2">↩</a></li>'
@@ -83,8 +83,8 @@ public function testAppearanceOrderNumberingAcrossParagraphs(): void
         $md = "First[^a].\n\nSecond[^b] and again[^b].\n\n[^a]: Def A.\n[^b]: Def B.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>First<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
-            . '<p>Second<sup><a href="#fn-2" id="fnref-2">2</a></sup> and again<sup><a href="#fn-2" id="fnref-2-2">2</a></sup>.</p>'
+            "<p>First<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
+            . "<p>Second<sup><a href=\"#fn-2\" id=\"fnref-2\">2</a></sup> and again<sup><a href=\"#fn-2\" id=\"fnref-2-2\">2</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Def A. <a href="#fnref-1">↩</a></li>'
             . '<li id="fn-2">Def B. <a href="#fnref-2">↩</a> <a href="#fnref-2-2">↩</a></li>'
@@ -101,7 +101,7 @@ public function testSameLabelTwiceProducesTwoBackLinks(): void
         $md = "First[^x] and second[^x].\n\n[^x]: Shared note.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>First<sup><a href="#fn-1" id="fnref-1">1</a></sup> and second<sup><a href="#fn-1" id="fnref-1-2">1</a></sup>.</p>'
+            "<p>First<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup> and second<sup><a href=\"#fn-1\" id=\"fnref-1-2\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Shared note. <a href="#fnref-1">↩</a> <a href="#fnref-1-2">↩</a></li>'
             . '</ol></section>',
@@ -124,7 +124,7 @@ public function testThirdOccurrenceSuffix(): void
     public function testUndefinedReferenceRendersLiteral(): void
     {
         $html = $this->renderMarkdown("See[^missing] for details.");
-        $this->assertSame('<p>See[^missing] for details.</p>', $html);
+        $this->assertSame("<p>See[^missing] for details.</p>\n", $html);
         $this->assertStringNotContainsString('<section', $html);
     }
 
@@ -134,7 +134,7 @@ public function testUndefinedReferenceRendersLiteral(): void
     public function testUnusedDefinitionOmitted(): void
     {
         $html = $this->renderMarkdown("Just a paragraph.\n\n[^unused]: Never referenced.");
-        $this->assertSame('<p>Just a paragraph.</p>', $html);
+        $this->assertSame("<p>Just a paragraph.</p>\n", $html);
         $this->assertStringNotContainsString('section', $html);
         $this->assertStringNotContainsString('unused', $html);
     }
@@ -147,7 +147,7 @@ public function testMultiLineBodyContinuation(): void
         $md = "Text[^ml].\n\n[^ml]: First line.\n    Second line, same footnote.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Text<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
+            "<p>Text<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">First line. Second line, same footnote. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -163,7 +163,7 @@ public function testFootnoteBodyWithInlineMarkup(): void
         $md = "Note[^fmt].\n\n[^fmt]: **Bold** and _italic_.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Note<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
+            "<p>Note<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1"><strong>Bold</strong> and <em>italic</em>. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -192,8 +192,8 @@ public function testSectionAtEndOfDocument(): void
         $md = "[^early]: Defined first.\n\nParagraph with reference[^early].\n\nAnother paragraph.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Paragraph with reference<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
-            . '<p>Another paragraph.</p>'
+            "<p>Paragraph with reference<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
+            . "<p>Another paragraph.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Defined first. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -207,7 +207,7 @@ public function testDefinitionBeforeReferencingParagraph(): void
         $md = "[^first]: Defined at top.\n\nParagraph with ref[^first].";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Paragraph with ref<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
+            "<p>Paragraph with ref<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Defined at top. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -255,7 +255,7 @@ public function testLabelCaseSensitive(): void
     {
         $md = "Ref[^Bar].\n\n[^bar]: Definition for bar.";
         $html = $this->renderMarkdown($md);
-        $this->assertSame('<p>Ref[^Bar].</p>', $html);
+        $this->assertSame("<p>Ref[^Bar].</p>\n", $html);
         $this->assertStringNotContainsString('section', $html);
     }
 
@@ -276,7 +276,7 @@ public function testLabelWithDigitsOnly(): void
         $md = "Ref[^123].\n\n[^123]: All digits.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Ref<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
+            "<p>Ref<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">All digits. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -290,7 +290,7 @@ public function testLabelWithHyphen(): void
         $md = "Ref[^my-note].\n\n[^my-note]: Hyphenated label.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p>Ref<sup><a href="#fn-1" id="fnref-1">1</a></sup>.</p>'
+            "<p>Ref<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup>.</p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Hyphenated label. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -302,7 +302,7 @@ public function testLabelWithHyphen(): void
     public function testLabelWithSpace_notMatched(): void
     {
         $html = $this->renderMarkdown("Ref[^bad label].");
-        $this->assertSame('<p>Ref[^bad label].</p>', $html);
+        $this->assertSame("<p>Ref[^bad label].</p>\n", $html);
     }
 
     /** EC-3: Definition with empty body (no text after colon) is rejected; ref renders as literal. */
@@ -323,7 +323,8 @@ public function testEmptyBodyDefinitionNotMatched(): void
     public function testListItemNotTokenizedAsDefinition(): void
     {
         $html = $this->renderMarkdown("- [^1]: This is a list item, not a footnote definition.");
-        $this->assertStringContainsString('<ul><li>', $html);
+        $this->assertStringContainsString('<ul>', $html);
+        $this->assertStringContainsString('<li>', $html);
         $this->assertStringContainsString('[^1]: This is a list item, not a footnote definition.', $html);
         $this->assertStringNotContainsString('<section', $html);
     }
@@ -334,7 +335,7 @@ public function testListItemNotTokenizedAsDefinition(): void
     public function testNoSectionWithZeroResolvedFootnotes(): void
     {
         $html = $this->renderMarkdown("Just text.");
-        $this->assertSame('<p>Just text.</p>', $html);
+        $this->assertSame("<p>Just text.</p>\n", $html);
         $this->assertStringNotContainsString('section', $html);
     }
 
@@ -346,7 +347,7 @@ public function testFootnoteRefInsideEmphasis(): void
         $md = "_text[^1]_\n\n[^1]: Inline note.";
         $html = $this->renderMarkdown($md);
         $this->assertSame(
-            '<p><em>text<sup><a href="#fn-1" id="fnref-1">1</a></sup></em></p>'
+            "<p><em>text<sup><a href=\"#fn-1\" id=\"fnref-1\">1</a></sup></em></p>\n"
             . '<section class="footnotes"><ol>'
             . '<li id="fn-1">Inline note. <a href="#fnref-1">↩</a></li>'
             . '</ol></section>',
@@ -393,7 +394,7 @@ public function testVeryLongLabel_notMatched(): void
     public function testEscapedBracketDoesNotTriggerFootnote(): void
     {
         $html = $this->renderMarkdown("\\[^1]");
-        $this->assertSame('<p>[^1]</p>', $html);
+        $this->assertSame("<p>[^1]</p>\n", $html);
         $this->assertStringNotContainsString('sup', $html);
     }
 
diff --git a/tests/Unit/IndentedCodeBlockTest.php b/tests/Unit/IndentedCodeBlockTest.php
index 23bd2be..a8401b1 100644
--- a/tests/Unit/IndentedCodeBlockTest.php
+++ b/tests/Unit/IndentedCodeBlockTest.php
@@ -108,7 +108,7 @@ public function testBasicIndentedBlockRendering(): void
     {
         $html = $this->render('    hello world');
 
-        $this->assertSame('<pre><code>hello world' . "\n" . '</code></pre>', $html);
+        $this->assertSame('<pre><code>hello world' . "\n" . "</code></pre>\n", $html);
     }
 
     public function testConsecutiveIndentedLinesFormSingleBlock(): void
@@ -124,14 +124,14 @@ public function testBlankLineInsideBlockIsPreserved(): void
     {
         $html = $this->render("    first\n\n    second");
 
-        $this->assertSame('<pre><code>first' . "\n\n" . 'second' . "\n" . '</code></pre>', $html);
+        $this->assertSame('<pre><code>first' . "\n\n" . 'second' . "\n" . "</code></pre>\n", $html);
     }
 
     public function testTrailingBlankLinesInsideBlockStripped(): void
     {
         $html = $this->render("    content\n\n\n");
 
-        $this->assertSame('<pre><code>content' . "\n" . '</code></pre>', $html);
+        $this->assertSame('<pre><code>content' . "\n" . "</code></pre>\n", $html);
     }
 
     public function testHtmlCharactersEscapedInContent(): void
@@ -190,7 +190,7 @@ public function testFiveSpaceIndentPreservesOneLeadingSpace(): void
         // AC-04: 5 spaces → 4 stripped, 1 space remains in content.
         $html = $this->render('     foo');
 
-        $this->assertSame('<pre><code> foo' . "\n" . '</code></pre>', $html);
+        $this->assertSame('<pre><code> foo' . "\n" . "</code></pre>\n", $html);
     }
 
     public function testNoClassAttributeOnCodeElement(): void
@@ -199,6 +199,6 @@ public function testNoClassAttributeOnCodeElement(): void
         $html = $this->render('    php');
 
         $this->assertStringNotContainsString('class=', $html);
-        $this->assertSame('<pre><code>php' . "\n" . '</code></pre>', $html);
+        $this->assertSame('<pre><code>php' . "\n" . "</code></pre>\n", $html);
     }
 }
diff --git a/tests/Unit/LinkAngleBracketUrlTest.php b/tests/Unit/LinkAngleBracketUrlTest.php
index 153d2e1..4947211 100644
--- a/tests/Unit/LinkAngleBracketUrlTest.php
+++ b/tests/Unit/LinkAngleBracketUrlTest.php
@@ -32,31 +32,31 @@ private function renderInline(string $input): string
     public function test_simple_angle_bracket_url(): void
     {
         $html = $this->renderInline('[foo](<https://example.com>)');
-        $this->assertSame('<p><a href="https://example.com">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\">foo</a></p>\n", $html);
     }
 
     public function test_angle_bracket_url_with_spaces(): void
     {
         $html = $this->renderInline('[foo](<my url with spaces>)');
-        $this->assertSame('<p><a href="my url with spaces">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"my url with spaces\">foo</a></p>\n", $html);
     }
 
     public function test_angle_bracket_empty_url(): void
     {
         $html = $this->renderInline('[foo](<>)');
-        $this->assertSame('<p><a href="">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"\">foo</a></p>\n", $html);
     }
 
     public function test_angle_bracket_url_with_title(): void
     {
         $html = $this->renderInline('[foo](<https://example.com> "title")');
-        $this->assertSame('<p><a href="https://example.com" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\" title=\"title\">foo</a></p>\n", $html);
     }
 
     public function test_angle_bracket_url_in_image(): void
     {
         $html = $this->renderInline('![alt](<https://example.com/img.png>)');
-        $this->assertSame('<p><img src="https://example.com/img.png" alt="alt"></p>', $html);
+        $this->assertSame("<p><img src=\"https://example.com/img.png\" alt=\"alt\" /></p>\n", $html);
     }
 
     public function test_unclosed_angle_bracket_is_not_a_link(): void
@@ -82,13 +82,13 @@ public function test_backslash_escaped_gt_in_angle_bracket_url(): void
         // \> in an angle-bracket URL is a backslash-escape for >; the rendered href
         // HTML-escapes the literal > to &gt; per standard attribute encoding.
         $html = $this->renderInline('[foo](<url\>bar>)');
-        $this->assertSame('<p><a href="url&gt;bar">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url&gt;bar\">foo</a></p>\n", $html);
     }
 
     public function test_ampersand_in_angle_bracket_url_is_escaped_in_href(): void
     {
         $html = $this->renderInline('[foo](<https://example.com?a=1&b=2>)');
-        $this->assertSame('<p><a href="https://example.com?a=1&amp;b=2">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com?a=1&amp;b=2\">foo</a></p>\n", $html);
     }
 
     public function test_cr_in_angle_bracket_url_is_rejected(): void
diff --git a/tests/Unit/LinkRefAngleBracketUrlTest.php b/tests/Unit/LinkRefAngleBracketUrlTest.php
index 2fe823d..8047471 100644
--- a/tests/Unit/LinkRefAngleBracketUrlTest.php
+++ b/tests/Unit/LinkRefAngleBracketUrlTest.php
@@ -38,35 +38,35 @@ private function renderMarkdown(string $markdown): string
     public function test_angle_bracket_url_brackets_are_stripped(): void
     {
         $html = $this->renderMarkdown("[foo]: <https://example.com>\n\n[foo]");
-        $this->assertSame('<p><a href="https://example.com">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\">foo</a></p>\n", $html);
     }
 
     /** AC-2: angle-bracket URL with double-quote title. */
     public function test_angle_bracket_url_with_double_quote_title(): void
     {
         $html = $this->renderMarkdown("[foo]: <https://example.com> \"title\"\n\n[foo]");
-        $this->assertSame('<p><a href="https://example.com" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-3: angle-bracket URL with single-quote title. */
     public function test_angle_bracket_url_with_single_quote_title(): void
     {
         $html = $this->renderMarkdown("[foo]: <https://example.com> 'title'\n\n[foo]");
-        $this->assertSame('<p><a href="https://example.com" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-4: empty angle brackets — href is an empty string. */
     public function test_empty_angle_brackets_produce_empty_href(): void
     {
         $html = $this->renderMarkdown("[foo]: <>\n\n[foo]");
-        $this->assertSame('<p><a href="">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"\">foo</a></p>\n", $html);
     }
 
     /** AC-5: angle-bracket URL used with an image reference. */
     public function test_angle_bracket_url_with_image_ref(): void
     {
         $html = $this->renderMarkdown("[img]: <https://example.com/img.png>\n\n![img]");
-        $this->assertSame('<p><img src="https://example.com/img.png" alt="img"></p>', $html);
+        $this->assertSame("<p><img src=\"https://example.com/img.png\" alt=\"img\" /></p>\n", $html);
     }
 
     /** AC-6: angle brackets stripped — only URL content stored (no brackets in href attr). */
@@ -96,7 +96,7 @@ public function test_backslash_escaped_gt_inside_angle_bracket_url(): void
     {
         // \> is unescaped to > during lexing; the renderer HTML-escapes > to &gt; in the attribute.
         $html = $this->renderMarkdown("[foo]: <url\\>path>\n\n[foo]");
-        $this->assertSame('<p><a href="url&gt;path">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url&gt;path\">foo</a></p>\n", $html);
     }
 
     /** Edge: unescaped < inside angle-bracket URL makes the definition invalid. */
@@ -110,27 +110,27 @@ public function test_unescaped_lt_inside_angle_bracket_url_is_invalid(): void
     public function test_ampersand_in_angle_bracket_url_is_html_escaped(): void
     {
         $html = $this->renderMarkdown("[foo]: <https://example.com?a=1&b=2>\n\n[foo]");
-        $this->assertSame('<p><a href="https://example.com?a=1&amp;b=2">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com?a=1&amp;b=2\">foo</a></p>\n", $html);
     }
 
     /** Edge: parenthesised title with angle-bracket URL (regression guard). */
     public function test_angle_bracket_url_with_paren_title(): void
     {
         $html = $this->renderMarkdown("[foo]: <https://example.com> (title)\n\n[foo]");
-        $this->assertSame('<p><a href="https://example.com" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** Regression: bare URL ref defs still work after the regex change. */
     public function test_bare_url_ref_def_still_works(): void
     {
         $html = $this->renderMarkdown("[foo]: https://example.com\n\n[foo]");
-        $this->assertSame('<p><a href="https://example.com">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"https://example.com\">foo</a></p>\n", $html);
     }
 
     /** Regression: bare URL ref def with title still works after the regex change. */
     public function test_bare_url_ref_def_with_title_still_works(): void
     {
         $html = $this->renderMarkdown("[foo]: /url \"a title\"\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="a title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"a title\">foo</a></p>\n", $html);
     }
 }
diff --git a/tests/Unit/LinkRefTitleVariantsTest.php b/tests/Unit/LinkRefTitleVariantsTest.php
index f09f9a4..58e320a 100644
--- a/tests/Unit/LinkRefTitleVariantsTest.php
+++ b/tests/Unit/LinkRefTitleVariantsTest.php
@@ -37,35 +37,35 @@ private function renderMarkdown(string $markdown): string
     public function test_ref_link_with_double_quote_title(): void
     {
         $html = $this->renderMarkdown("[foo]: /url \"title\"\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-2: single-quote title. */
     public function test_ref_link_with_single_quote_title(): void
     {
         $html = $this->renderMarkdown("[foo]: /url 'title'\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-3: parenthesised title. */
     public function test_ref_link_with_parenthesised_title(): void
     {
         $html = $this->renderMarkdown("[foo]: /url (title)\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-4: image ref with single-quote title. */
     public function test_ref_image_with_single_quote_title(): void
     {
         $html = $this->renderMarkdown("[img]: /img.png 'alt title'\n\n![img]");
-        $this->assertSame('<p><img src="/img.png" alt="img" title="alt title"></p>', $html);
+        $this->assertSame("<p><img src=\"/img.png\" alt=\"img\" title=\"alt title\" /></p>\n", $html);
     }
 
     /** AC-5: title on a separate continuation line (CommonMark §4.7). */
     public function test_ref_link_with_title_on_separate_line(): void
     {
         $html = $this->renderMarkdown("[foo]: /url\n'title'\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /**
@@ -82,7 +82,7 @@ public function test_mismatched_title_delimiters_not_a_valid_def(): void
     public function test_ref_link_with_no_title(): void
     {
         $html = $this->renderMarkdown("[foo]: /url\n\n[foo]");
-        $this->assertSame('<p><a href="/url">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\">foo</a></p>\n", $html);
     }
 
     /** Edge: parenthesised title must not contain unescaped ( — treated as invalid. */
@@ -114,20 +114,20 @@ public function test_double_quote_title_may_contain_single_quotes(): void
     public function test_ref_link_with_double_quote_title_on_separate_line(): void
     {
         $html = $this->renderMarkdown("[foo]: /url\n\"title\"\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** Edge: title on separate line with parenthesised delimiter. */
     public function test_ref_link_with_paren_title_on_separate_line(): void
     {
         $html = $this->renderMarkdown("[foo]: /url\n(title)\n\n[foo]");
-        $this->assertSame('<p><a href="/url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"/url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** Edge: orphan title line not preceded by a URL-only ref def must NOT be consumed as a title. */
     public function test_orphan_title_line_not_consumed_as_title(): void
     {
         $html = $this->renderMarkdown("'orphan'\n\n[foo]: /url\n\n[foo]");
-        $this->assertSame('<p>&#039;orphan&#039;</p><p><a href="/url">foo</a></p>', $html);
+        $this->assertSame("<p>&#039;orphan&#039;</p>\n<p><a href=\"/url\">foo</a></p>\n", $html);
     }
 }
diff --git a/tests/Unit/LinkTitleVariantsTest.php b/tests/Unit/LinkTitleVariantsTest.php
index 97a86be..5494645 100644
--- a/tests/Unit/LinkTitleVariantsTest.php
+++ b/tests/Unit/LinkTitleVariantsTest.php
@@ -33,49 +33,49 @@ private function renderInline(string $input): string
     public function test_link_with_double_quote_title(): void
     {
         $html = $this->renderInline('[foo](url "title")');
-        $this->assertSame('<p><a href="url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-2: single-quote title on a plain link. */
     public function test_link_with_single_quote_title(): void
     {
         $html = $this->renderInline("[foo](url 'title')");
-        $this->assertSame('<p><a href="url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-3: parenthesised title on a plain link. */
     public function test_link_with_parenthesised_title(): void
     {
         $html = $this->renderInline('[foo](url (title))');
-        $this->assertSame('<p><a href="url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-4: single-quote title on an image. */
     public function test_image_with_single_quote_title(): void
     {
         $html = $this->renderInline("![alt](img.png 'title')");
-        $this->assertSame('<p><img src="img.png" alt="alt" title="title"></p>', $html);
+        $this->assertSame("<p><img src=\"img.png\" alt=\"alt\" title=\"title\" /></p>\n", $html);
     }
 
     /** AC-5: parenthesised title on an image. */
     public function test_image_with_parenthesised_title(): void
     {
         $html = $this->renderInline('![alt](img.png (title))');
-        $this->assertSame('<p><img src="img.png" alt="alt" title="title"></p>', $html);
+        $this->assertSame("<p><img src=\"img.png\" alt=\"alt\" title=\"title\" /></p>\n", $html);
     }
 
     /** AC-6: single-quote title with angle-bracket URL. */
     public function test_angle_bracket_url_link_with_single_quote_title(): void
     {
         $html = $this->renderInline("[foo](<url> 'title')");
-        $this->assertSame('<p><a href="url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /** AC-7: parenthesised title with angle-bracket URL. */
     public function test_angle_bracket_url_link_with_parenthesised_title(): void
     {
         $html = $this->renderInline('[foo](<url> (title))');
-        $this->assertSame('<p><a href="url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /**
@@ -93,7 +93,7 @@ public function test_single_quote_title_with_escaped_inner_quote(): void
     {
         // The renderer applies htmlspecialchars(ENT_QUOTES), so ' is encoded as &#039; in attributes.
         $html = $this->renderInline("[foo](url 'it\\'s')");
-        $this->assertSame('<p><a href="url" title="it&#039;s">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"it&#039;s\">foo</a></p>\n", $html);
     }
 
     /**
@@ -121,7 +121,7 @@ public function test_no_whitespace_before_title_delimiter_not_a_title(): void
     public function test_trailing_whitespace_before_close_paren_is_tolerated(): void
     {
         $html = $this->renderInline("[foo](url 'title'   )");
-        $this->assertSame('<p><a href="url" title="title">foo</a></p>', $html);
+        $this->assertSame("<p><a href=\"url\" title=\"title\">foo</a></p>\n", $html);
     }
 
     /**
@@ -139,6 +139,6 @@ public function test_non_whitespace_after_title_close_delimiter_invalidates_titl
     public function test_image_angle_bracket_url_with_double_quote_title_regression(): void
     {
         $html = $this->renderInline('![alt](<img.png> "title")');
-        $this->assertSame('<p><img src="img.png" alt="alt" title="title"></p>', $html);
+        $this->assertSame("<p><img src=\"img.png\" alt=\"alt\" title=\"title\" /></p>\n", $html);
     }
 }
diff --git a/tests/Unit/LooseTightListTest.php b/tests/Unit/LooseTightListTest.php
index a060a3d..3e5f502 100644
--- a/tests/Unit/LooseTightListTest.php
+++ b/tests/Unit/LooseTightListTest.php
@@ -56,9 +56,9 @@ public function testLooseUnorderedList(): void
         $html = $this->render("- foo\n\n- bar\n\n- baz");
 
         $this->assertStringContainsString('<ul>', $html);
-        $this->assertStringContainsString('<li><p>foo</p></li>', $html);
-        $this->assertStringContainsString('<li><p>bar</p></li>', $html);
-        $this->assertStringContainsString('<li><p>baz</p></li>', $html);
+        $this->assertStringContainsString("<li>\n<p>foo</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>bar</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>baz</p>\n</li>", $html);
     }
 
     // -------------------------------------------------------------------------
@@ -71,9 +71,9 @@ public function testOneBlankMakesAllLoose(): void
         $html = $this->render("- alpha\n- beta\n\n- gamma");
 
         // All three items must be wrapped in <p>.
-        $this->assertStringContainsString('<li><p>alpha</p></li>', $html);
-        $this->assertStringContainsString('<li><p>beta</p></li>', $html);
-        $this->assertStringContainsString('<li><p>gamma</p></li>', $html);
+        $this->assertStringContainsString("<li>\n<p>alpha</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>beta</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>gamma</p>\n</li>", $html);
     }
 
     // -------------------------------------------------------------------------
@@ -100,9 +100,9 @@ public function testLooseOrderedList(): void
         $html = $this->render("1. one\n\n2. two\n\n3. three");
 
         $this->assertStringContainsString('<ol>', $html);
-        $this->assertStringContainsString('<li><p>one</p></li>', $html);
-        $this->assertStringContainsString('<li><p>two</p></li>', $html);
-        $this->assertStringContainsString('<li><p>three</p></li>', $html);
+        $this->assertStringContainsString("<li>\n<p>one</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>two</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>three</p>\n</li>", $html);
     }
 
     // -------------------------------------------------------------------------
@@ -183,9 +183,9 @@ public function testMidListBlankMakesLoose(): void
         // the whole list loose, so x must also be wrapped in <p>.
         $html = $this->render("- x\n- y\n\n- z");
 
-        $this->assertStringContainsString('<li><p>x</p></li>', $html);
-        $this->assertStringContainsString('<li><p>y</p></li>', $html);
-        $this->assertStringContainsString('<li><p>z</p></li>', $html);
+        $this->assertStringContainsString("<li>\n<p>x</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>y</p>\n</li>", $html);
+        $this->assertStringContainsString("<li>\n<p>z</p>\n</li>", $html);
     }
 
     // -------------------------------------------------------------------------
@@ -239,7 +239,7 @@ public function testRendererWrapsInParaWhenLoose(): void
 
         $html = $this->renderer->render($doc);
 
-        $this->assertStringContainsString('<li><p>hello</p></li>', $html);
+        $this->assertStringContainsString("<li>\n<p>hello</p>\n</li>", $html);
     }
 
     // -------------------------------------------------------------------------
diff --git a/tests/Unit/Renderer/XhtmlOutputFormatTest.php b/tests/Unit/Renderer/XhtmlOutputFormatTest.php
new file mode 100644
index 0000000..cee5694
--- /dev/null
+++ b/tests/Unit/Renderer/XhtmlOutputFormatTest.php
@@ -0,0 +1,153 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpMarkdown\Tests\Unit\Renderer;
+
+use PhpMarkdown\MarkdownParser;
+use PHPUnit\Framework\Attributes\RequiresPhpExtension;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Acceptance tests for XHTML-compatible output format.
+ *
+ * All block elements must end with a newline.
+ * Void elements (<hr>, <br>, <img>) must use self-closing syntax.
+ * Inline nodes must produce no trailing newline of their own.
+ */
+#[RequiresPhpExtension('intl')]
+final class XhtmlOutputFormatTest extends TestCase
+{
+    private MarkdownParser $parser;
+
+    protected function setUp(): void
+    {
+        $this->parser = new MarkdownParser();
+    }
+
+    private function parseAndRender(string $markdown): string
+    {
+        return $this->parser->parse($markdown);
+    }
+
+    // ── Headings ──────────────────────────────────────────────────────────────
+
+    public function testAtxHeadingLevel1EndsWithNewline(): void
+    {
+        $out = $this->parseAndRender('# Foo');
+        $this->assertSame("<h1>Foo</h1>\n", $out);
+    }
+
+    public function testAtxHeadingLevel2EndsWithNewline(): void
+    {
+        $out = $this->parseAndRender('## Bar');
+        $this->assertSame("<h2>Bar</h2>\n", $out);
+    }
+
+    // ── Paragraph ─────────────────────────────────────────────────────────────
+
+    public function testParagraphEndsWithNewline(): void
+    {
+        $out = $this->parseAndRender('hello');
+        $this->assertSame("<p>hello</p>\n", $out);
+    }
+
+    // ── Code blocks ───────────────────────────────────────────────────────────
+
+    public function testIndentedCodeBlockEndsWithNewline(): void
+    {
+        $out = $this->parseAndRender("    a simple\n      indented code block");
+        $this->assertSame("<pre><code>a simple\n  indented code block\n</code></pre>\n", $out);
+    }
+
+    public function testFencedCodeBlockEndsWithNewline(): void
+    {
+        $out = $this->parseAndRender("```\n<\n >\n```");
+        // The lexer preserves content as-is; the renderer wraps in <pre><code>...</code></pre>\n.
+        $this->assertSame("<pre><code>&lt;\n &gt;</code></pre>\n", $out);
+    }
+
+    public function testFencedCodeBlockWithLanguageEndsWithNewline(): void
+    {
+        $out = $this->parseAndRender("```php\necho 1;\n```");
+        $this->assertSame("<pre><code class=\"language-php\">echo 1;</code></pre>\n", $out);
+    }
+
+    // ── Void elements: self-closing syntax ────────────────────────────────────
+
+    public function testHorizontalRuleRendersAsSelfClosingWithNewline(): void
+    {
+        $out = $this->parseAndRender('***');
+        $this->assertSame("<hr />\n", $out);
+    }
+
+    public function testHardLineBreakRendersAsSelfClosingWithTrailingNewline(): void
+    {
+        $out = $this->parseAndRender("foo  \nbar");
+        $this->assertSame("<p>foo<br />\nbar</p>\n", $out);
+    }
+
+    public function testImageRendersAsSelfClosingWithTitleAttribute(): void
+    {
+        $out = $this->parseAndRender('![alt](/url "title")');
+        $this->assertSame("<p><img src=\"/url\" alt=\"alt\" title=\"title\" /></p>\n", $out);
+    }
+
+    public function testImageWithoutTitleRendersAsSelfClosing(): void
+    {
+        $out = $this->parseAndRender('![alt](/url)');
+        $this->assertSame("<p><img src=\"/url\" alt=\"alt\" /></p>\n", $out);
+    }
+
+    // ── Blockquotes ───────────────────────────────────────────────────────────
+
+    public function testBlockquoteHasInternalNewlines(): void
+    {
+        $out = $this->parseAndRender('> bar');
+        $this->assertSame("<blockquote>\n<p>bar</p>\n</blockquote>\n", $out);
+    }
+
+    public function testNestedBlockquoteHasNewlinesAtEveryLevel(): void
+    {
+        $out = $this->parseAndRender('> > nested');
+        $this->assertSame("<blockquote>\n<blockquote>\n<p>nested</p>\n</blockquote>\n</blockquote>\n", $out);
+    }
+
+    // ── Lists ─────────────────────────────────────────────────────────────────
+
+    public function testTightUnorderedListHasNewlines(): void
+    {
+        $out = $this->parseAndRender("- foo\n- bar");
+        $this->assertSame("<ul>\n<li>foo</li>\n<li>bar</li>\n</ul>\n", $out);
+    }
+
+    public function testTightOrderedListHasNewlines(): void
+    {
+        $out = $this->parseAndRender("1. foo\n2. bar");
+        $this->assertSame("<ol>\n<li>foo</li>\n<li>bar</li>\n</ol>\n", $out);
+    }
+
+    public function testLooseUnorderedListWrapsItemsInParagraph(): void
+    {
+        $out = $this->parseAndRender("- foo\n\n- bar");
+        $this->assertSame("<ul>\n<li>\n<p>foo</p>\n</li>\n<li>\n<p>bar</p>\n</li>\n</ul>\n", $out);
+    }
+
+    // ── Inline nodes: no trailing newline of their own ────────────────────────
+
+    public function testInlineNodesHaveNoTrailingNewline(): void
+    {
+        // Strong, link, and code are all inline — the outer <p> carries the \n,
+        // no inline node should inject a newline between itself and its siblings.
+        $out = $this->parseAndRender('**bold** [link](https://example.com) `code`');
+
+        // Outer paragraph ends with exactly one newline.
+        $this->assertStringEndsWith("</p>\n", $out);
+
+        // The string between <p> and </p> must contain no raw newlines
+        // (only the paragraph wrapper provides the trailing \n).
+        preg_match('/<p>(.*?)<\/p>/s', $out, $matches);
+        $this->assertArrayHasKey(1, $matches);
+        $this->assertStringNotContainsString("\n", $matches[1]);
+    }
+}
diff --git a/tests/Unit/RendererEntityTest.php b/tests/Unit/RendererEntityTest.php
index c53ddfb..bfbf18f 100644
--- a/tests/Unit/RendererEntityTest.php
+++ b/tests/Unit/RendererEntityTest.php
@@ -31,21 +31,21 @@ public function testHtmlEntityNodeRenderedVerbatim(): void
         $out = $this->render([new ParagraphNode([new HtmlEntityNode('&amp;')])]);
 
         // Must be &amp; exactly — no double-escaping to &amp;amp;
-        $this->assertSame('<p>&amp;</p>', $out);
+        $this->assertSame("<p>&amp;</p>\n", $out);
     }
 
     public function testHtmlEntityNodeLtRenderedVerbatim(): void
     {
         $out = $this->render([new ParagraphNode([new HtmlEntityNode('&lt;')])]);
 
-        $this->assertSame('<p>&lt;</p>', $out);
+        $this->assertSame("<p>&lt;</p>\n", $out);
     }
 
     public function testHtmlEntityNodeHexRenderedVerbatim(): void
     {
         $out = $this->render([new ParagraphNode([new HtmlEntityNode('&#x00A0;')])]);
 
-        $this->assertSame('<p>&#x00A0;</p>', $out);
+        $this->assertSame("<p>&#x00A0;</p>\n", $out);
     }
 
     public function testTextNodeBareAmpersandIsEscaped(): void
@@ -53,6 +53,6 @@ public function testTextNodeBareAmpersandIsEscaped(): void
         // Regression guard: TextNode('a & b') must still produce a &amp; b.
         $out = $this->render([new ParagraphNode([new TextNode('a & b')])]);
 
-        $this->assertSame('<p>a &amp; b</p>', $out);
+        $this->assertSame("<p>a &amp; b</p>\n", $out);
     }
 }
diff --git a/tests/Unit/RendererTest.php b/tests/Unit/RendererTest.php
index 2f4ce2a..a6ad6ef 100644
--- a/tests/Unit/RendererTest.php
+++ b/tests/Unit/RendererTest.php
@@ -62,7 +62,7 @@ public static function headingProvider(): array
     {
         return array_combine(
             array_map(fn($l) => "h{$l}", range(1, 6)),
-            array_map(fn($l) => [$l, "<h{$l}>T</h{$l}>"], range(1, 6)),
+            array_map(fn($l) => [$l, "<h{$l}>T</h{$l}>\n"], range(1, 6)),
         );
     }
 
@@ -77,7 +77,7 @@ public function testXssInTextNodeEscaped(): void
     public function testAmpersandEscaped(): void
     {
         $out = $this->render([new ParagraphNode([new TextNode('a & b')])]);
-        $this->assertSame('<p>a &amp; b</p>', $out);
+        $this->assertSame("<p>a &amp; b</p>\n", $out);
     }
 
     public function testQuoteEscapedInAttribute(): void
@@ -91,7 +91,7 @@ public function testLinkRendered(): void
         $out = $this->render([new ParagraphNode([
             new LinkNode('https://example.com', [new TextNode('click')]),
         ])]);
-        $this->assertSame('<p><a href="https://example.com">click</a></p>', $out);
+        $this->assertSame("<p><a href=\"https://example.com\">click</a></p>\n", $out);
     }
 
     public function testLinkHrefEscaped(): void
@@ -106,13 +106,13 @@ public function testLinkHrefEscaped(): void
     public function testImageRendered(): void
     {
         $out = $this->render([new ParagraphNode([new ImageNode('img.png', 'desc')])]);
-        $this->assertSame('<p><img src="img.png" alt="desc"></p>', $out);
+        $this->assertSame("<p><img src=\"img.png\" alt=\"desc\" /></p>\n", $out);
     }
 
     public function testImageWithTitleRendered(): void
     {
         $out = $this->render([new ParagraphNode([new ImageNode('img.png', 'alt text', 'My tooltip')])]);
-        $this->assertSame('<p><img src="img.png" alt="alt text" title="My tooltip"></p>', $out);
+        $this->assertSame("<p><img src=\"img.png\" alt=\"alt text\" title=\"My tooltip\" /></p>\n", $out);
     }
 
     public function testImageTitleEscaped(): void
@@ -124,7 +124,7 @@ public function testImageTitleEscaped(): void
     public function testFencedCodeWithLanguage(): void
     {
         $out = $this->render([new FencedCodeNode("echo 'x';", 'php')]);
-        $this->assertSame('<pre><code class="language-php">echo &#039;x&#039;;</code></pre>', $out);
+        $this->assertSame("<pre><code class=\"language-php\">echo &#039;x&#039;;</code></pre>\n", $out);
     }
 
     public function testFencedCodeContentEscaped(): void
@@ -139,7 +139,7 @@ public function testUnorderedList(): void
             new ListItemNode([new TextNode('a')]),
             new ListItemNode([new TextNode('b')]),
         ])]);
-        $this->assertSame('<ul><li>a</li><li>b</li></ul>', $out);
+        $this->assertSame("<ul>\n<li>a</li>\n<li>b</li>\n</ul>\n", $out);
     }
 
     public function testOrderedList(): void
@@ -147,7 +147,7 @@ public function testOrderedList(): void
         $out = $this->render([new ListNode(ordered: true, children: [
             new ListItemNode([new TextNode('a')]),
         ])]);
-        $this->assertSame('<ol><li>a</li></ol>', $out);
+        $this->assertSame("<ol>\n<li>a</li>\n</ol>\n", $out);
     }
 
     public function testBlockquoteRendered(): void
@@ -155,7 +155,7 @@ public function testBlockquoteRendered(): void
         $out = $this->render([new BlockquoteNode([
             new ParagraphNode([new TextNode('quote')]),
         ])]);
-        $this->assertSame('<blockquote><p>quote</p></blockquote>', $out);
+        $this->assertSame("<blockquote>\n<p>quote</p>\n</blockquote>\n", $out);
     }
 
     public function testNestedBlockquoteRendered(): void
@@ -167,7 +167,7 @@ public function testNestedBlockquoteRendered(): void
                 ]),
             ]),
         ]);
-        $this->assertSame('<blockquote><blockquote><p>deep</p></blockquote></blockquote>', $out);
+        $this->assertSame("<blockquote>\n<blockquote>\n<p>deep</p>\n</blockquote>\n</blockquote>\n", $out);
     }
 
     public function testBlockquoteMixedChildrenRendered(): void
@@ -182,7 +182,7 @@ public function testBlockquoteMixedChildrenRendered(): void
             ]),
         ]);
         $this->assertSame(
-            '<blockquote><p>outer</p><blockquote><p>inner</p></blockquote><p>outer again</p></blockquote>',
+            "<blockquote>\n<p>outer</p>\n<blockquote>\n<p>inner</p>\n</blockquote>\n<p>outer again</p>\n</blockquote>\n",
             $out,
         );
     }
@@ -194,19 +194,19 @@ public function testBlockquoteWithInlineMarkupRendered(): void
                 new ParagraphNode([new StrongNode([new TextNode('bold')])]),
             ]),
         ]);
-        $this->assertSame('<blockquote><p><strong>bold</strong></p></blockquote>', $out);
+        $this->assertSame("<blockquote>\n<p><strong>bold</strong></p>\n</blockquote>\n", $out);
     }
 
     public function testHorizontalRuleRendered(): void
     {
         $out = $this->render([new HorizontalRuleNode()]);
-        $this->assertSame('<hr>', $out);
+        $this->assertSame("<hr />\n", $out);
     }
 
     public function testInlineCodeEscaped(): void
     {
         $out = $this->render([new ParagraphNode([new CodeNode('<b>')])]);
-        $this->assertSame('<p><code>&lt;b&gt;</code></p>', $out);
+        $this->assertSame("<p><code>&lt;b&gt;</code></p>\n", $out);
     }
 
     public function testStrongAndEmRendered(): void
@@ -215,7 +215,7 @@ public function testStrongAndEmRendered(): void
             new StrongNode([new TextNode('b')]),
             new EmphasisNode([new TextNode('i')]),
         ])]);
-        $this->assertSame('<p><strong>b</strong><em>i</em></p>', $out);
+        $this->assertSame("<p><strong>b</strong><em>i</em></p>\n", $out);
     }
 
     public function testTableRendered(): void
@@ -335,13 +335,13 @@ public function testMixedDocumentMermaidAndCodeBlock(): void
     public function testStrikethroughRendered(): void
     {
         $out = $this->render([new ParagraphNode([new StrikethroughNode([new TextNode('foo')])])]);
-        $this->assertSame('<p><del>foo</del></p>', $out);
+        $this->assertSame("<p><del>foo</del></p>\n", $out);
     }
 
     public function testStrikethroughXssEscaped(): void
     {
         $out = $this->render([new ParagraphNode([new StrikethroughNode([new TextNode('<b>')])])]);
-        $this->assertSame('<p><del>&lt;b&gt;</del></p>', $out);
+        $this->assertSame("<p><del>&lt;b&gt;</del></p>\n", $out);
     }
 
     // ── Nested list rendering ────────────────────────────────────────────────
@@ -358,7 +358,7 @@ public function testNestedUnorderedList(): void
                 ]),
             ]),
         ]);
-        $this->assertSame('<ul><li>a<ul><li>b</li></ul></li></ul>', $out);
+        $this->assertSame("<ul>\n<li>a<ul>\n<li>b</li>\n</ul>\n</li>\n</ul>\n", $out);
     }
 
     public function testMixedOrderedUnorderedNesting(): void
@@ -373,7 +373,7 @@ public function testMixedOrderedUnorderedNesting(): void
                 ]),
             ]),
         ]);
-        $this->assertSame('<ol><li>first<ul><li>nested</li></ul></li></ol>', $out);
+        $this->assertSame("<ol>\n<li>first<ul>\n<li>nested</li>\n</ul>\n</li>\n</ol>\n", $out);
     }
 
     // ── Task list (checkbox) rendering ───────────────────────────────────────
@@ -383,7 +383,7 @@ public function testCheckedListItemRendersCheckbox(): void
         $out = $this->render([new ListNode(ordered: false, children: [
             new ListItemNode([new TextNode('Done')], checked: true),
         ])]);
-        $this->assertSame('<ul><li><input type="checkbox" disabled checked> Done</li></ul>', $out);
+        $this->assertSame("<ul>\n<li><input type=\"checkbox\" disabled checked> Done</li>\n</ul>\n", $out);
     }
 
     public function testUncheckedListItemRendersCheckbox(): void
@@ -391,7 +391,7 @@ public function testUncheckedListItemRendersCheckbox(): void
         $out = $this->render([new ListNode(ordered: false, children: [
             new ListItemNode([new TextNode('Todo')], checked: false),
         ])]);
-        $this->assertSame('<ul><li><input type="checkbox" disabled> Todo</li></ul>', $out);
+        $this->assertSame("<ul>\n<li><input type=\"checkbox\" disabled> Todo</li>\n</ul>\n", $out);
     }
 
     public function testPlainListItemNoCheckbox(): void
@@ -399,7 +399,7 @@ public function testPlainListItemNoCheckbox(): void
         $out = $this->render([new ListNode(ordered: false, children: [
             new ListItemNode([new TextNode('plain')], checked: null),
         ])]);
-        $this->assertSame('<ul><li>plain</li></ul>', $out);
+        $this->assertSame("<ul>\n<li>plain</li>\n</ul>\n", $out);
     }
 
     public function testCheckedListItemWithNoChildrenHasTrailingSpace(): void
@@ -409,7 +409,7 @@ public function testCheckedListItemWithNoChildrenHasTrailingSpace(): void
         $out = $this->render([new ListNode(ordered: false, children: [
             new ListItemNode([], checked: true),
         ])]);
-        $this->assertSame('<ul><li><input type="checkbox" disabled checked> </li></ul>', $out);
+        $this->assertSame("<ul>\n<li><input type=\"checkbox\" disabled checked> </li>\n</ul>\n", $out);
     }
 
     // ── HardBreakNode rendering ──────────────────────────────────────────────
@@ -422,7 +422,7 @@ public function testHardBreakNodeRendersAsBr(): void
             new HardBreakNode(),
             new TextNode('bar'),
         ])]);
-        $this->assertSame('<p>foo<br>bar</p>', $out);
+        $this->assertSame("<p>foo<br />\nbar</p>\n", $out);
     }
 
     public function testHardBreakNodeAloneRendersAsBr(): void
@@ -431,7 +431,7 @@ public function testHardBreakNodeAloneRendersAsBr(): void
         $out = $this->render([new ParagraphNode([
             new HardBreakNode(),
         ])]);
-        $this->assertSame('<p><br></p>', $out);
+        $this->assertSame("<p><br />\n</p>\n", $out);
     }
 
     // ── RawHtmlInlineNode rendering ────────────────────────────────────────────
@@ -440,7 +440,7 @@ public function testRawHtmlInlineNodeContentIsEscaped(): void
     {
         // S29 escaped-fallback contract: tag chars become HTML entities.
         $out = $this->render([new ParagraphNode([new RawHtmlInlineNode('<span class="hi">')])]);
-        $this->assertSame('<p>&lt;span class=&quot;hi&quot;&gt;</p>', $out);
+        $this->assertSame("<p>&lt;span class=&quot;hi&quot;&gt;</p>\n", $out);
     }
 
     public function testRawHtmlInlineScriptNodeIsEscaped(): void
@@ -457,7 +457,7 @@ public function testRawHtmlInlineNodeInHeadingChildren(): void
             new TextNode('1'),
             new RawHtmlInlineNode('</sup>'),
         ])]);
-        $this->assertSame('<h1>&lt;sup&gt;1&lt;/sup&gt;</h1>', $out);
+        $this->assertSame("<h1>&lt;sup&gt;1&lt;/sup&gt;</h1>\n", $out);
     }
 
     public function testRawHtmlInlineNodeMixedWithText(): void
@@ -469,7 +469,7 @@ public function testRawHtmlInlineNodeMixedWithText(): void
             new RawHtmlInlineNode('</span>'),
             new TextNode(' more'),
         ])]);
-        $this->assertSame('<p>text &lt;span&gt;word&lt;/span&gt; more</p>', $out);
+        $this->assertSame("<p>text &lt;span&gt;word&lt;/span&gt; more</p>\n", $out);
     }
 
     // ── RawHtmlBlockNode rendering ─────────────────────────────────────────────
@@ -480,7 +480,7 @@ public function testRawHtmlBlockNodeEscapedByDefault(): void
         $out = (new HtmlRenderer())->render(new DocumentNode([
             new RawHtmlBlockNode('<div>x</div>'),
         ]));
-        $this->assertSame('&lt;div&gt;x&lt;/div&gt;', $out);
+        $this->assertSame("&lt;div&gt;x&lt;/div&gt;\n", $out);
     }
 
     public function testRawHtmlBlockNodeSanitizedWhenAllowed(): void
@@ -555,7 +555,7 @@ public function testHtmlEntityNodeVerbatimByDefault(): void
         $out = (new HtmlRenderer())->render(new DocumentNode([
             new ParagraphNode([new HtmlEntityNode('&amp;')]),
         ]));
-        $this->assertSame('<p>&amp;</p>', $out);
+        $this->assertSame("<p>&amp;</p>\n", $out);
     }
 
     public function testHtmlEntityNodeVerbatimWhenAllowRawHtmlEnabled(): void
@@ -564,6 +564,6 @@ public function testHtmlEntityNodeVerbatimWhenAllowRawHtmlEnabled(): void
         $out = (new HtmlRenderer(allowRawHtml: true))->render(new DocumentNode([
             new ParagraphNode([new HtmlEntityNode('&amp;')]),
         ]));
-        $this->assertSame('<p>&amp;</p>', $out);
+        $this->assertSame("<p>&amp;</p>\n", $out);
     }
 }
diff --git a/tests/Unit/SetextHeadingMultilineTest.php b/tests/Unit/SetextHeadingMultilineTest.php
index ad3f953..c5261af 100644
--- a/tests/Unit/SetextHeadingMultilineTest.php
+++ b/tests/Unit/SetextHeadingMultilineTest.php
@@ -147,7 +147,7 @@ public function testSingleLineRegressionRenders(): void
 
     public function testBlankBreaksAccumulationRenders(): void
     {
-        self::assertSame('<p>foo</p><h1>bar</h1>', $this->render("foo\n\nbar\n==="));
+        self::assertSame("<p>foo</p>\n<h1>bar</h1>", $this->render("foo\n\nbar\n==="));
     }
 
     public function testInlineMarkupSpansLinesRenders(): void