Fix #2143: keep NUnit2.5 mixed suite results valid

src/functions/TestResults.NUnit25.ps1

@@ -100,11 +100,14 @@
 
     $XmlWriter.WriteStartElement('results')
 
+    $hasRunnableChildBlocks = $false
     foreach ($action in $Node.Blocks) {
         if (-not $action.ShouldRun) {
             # skip blocks that were discovered but did not run
             continue
         }
+
+        $hasRunnableChildBlocks = $true
         Write-NUnitTestSuiteElements -Node $action -XmlWriter $XmlWriter -Path $action.ExpandedPath
     }
 
@@ -114,6 +117,9 @@
         $Node.Tests | & $SafeCommands['Group-Object'] -Property GroupId | & $SafeCommands["Sort-Object"] -Property Name
     )
 
+    $hasParameterizedTestSuites = 0 -lt @($suites | & $SafeCommands['Where-Object'] { $_.Name }).Count
+    $requiresTestCaseWrapper = $hasRunnableChildBlocks -or $hasParameterizedTestSuites
+
     foreach ($suite in $suites) {
         # When group has name it is a parameterized tests (data-generated using -ForEach/TestCases) so we want extra level of nesting for them
         $testGroupId = $suite.Name
@@ -133,8 +139,21 @@
                 continue
             }
 
+            if (-not $testGroupId -and $requiresTestCaseWrapper) {
+                $testCaseSuiteInfo = Get-TestSuiteInfoForTestResult -TestResult $testCase
+
+                $XmlWriter.WriteStartElement('test-suite')
+                Write-NUnitTestSuiteAttributes -TestSuiteInfo $testCaseSuiteInfo -XmlWriter $XmlWriter
+                $XmlWriter.WriteStartElement('results')
+            }
+
             $suiteName = if ($testGroupId) { $parameterizedSuiteInfo.Name } else { '' }
             Write-NUnitTestCaseElement -TestResult $testCase -XmlWriter $XmlWriter -Path ($testCase.Path -join '.') -ParameterizedSuiteName $suiteName
+
+            if (-not $testGroupId -and $requiresTestCaseWrapper) {
+                $XmlWriter.WriteEndElement()
+                $XmlWriter.WriteEndElement()
+            }
         }
 
         if ($testGroupId) {
@@ -186,6 +205,25 @@
     return Get-TestSuiteInfo -TestSuite $node -Path $node.Path
 }
 
+function Get-TestSuiteInfoForTestResult {
+    param($TestResult)
+
+    $node = [PSCustomObject] @{
+        Duration          = $TestResult.Duration
+        FailedCount       = 0
+        SkippedCount      = 0
+        InconclusiveCount = 0
+    }
+
+    switch ($TestResult.Result) {
+        Failed { $node.FailedCount = 1; break }
+        Skipped { $node.SkippedCount = 1; break }
+        Inconclusive { $node.InconclusiveCount = 1; break }
+    }
+
+    return Get-TestSuiteInfo -TestSuite $node -Path $TestResult.Path
+}
+
 function Get-TestSuiteInfo {
     param($TestSuite, $Path)
     # if (-not $Path) {

tst/Pester.RSpec.TestResults.NUnit25.ts.ps1

@@ -436,6 +436,29 @@ i -PassThru:$PassThru {
             $null = $xmlResult.Schemas.Add($null, $schemaPath)
             $xmlResult.Validate( { throw $args[1].Exception })
         }
+
+        t 'Should validate against the nunit 2.5 schema when ForEach and plain tests are mixed' {
+            # https://github.com/pester/Pester/issues/2143
+            $sb = {
+                Describe 'Demonstrate NUnit Problem' {
+                    It 'Should return <Result> when type is <Type>' -ForEach @(
+                        @{ Type = 'String'; Variable = [String]'Test'; Result = $true }
+                        @{ Type = 'Int'; Variable = [Int]0; Result = $false }
+                    ) {
+                        ($Variable -is [String]) | Should -Be $Result
+                    }
+
+                    It 'A plain non-parameterized test' { 1 | Should -Be 1 }
+                }
+            }
+            $r = Invoke-Pester -Configuration ([PesterConfiguration]@{ Run = @{ ScriptBlock = $sb; PassThru = $true }; Output = @{ Verbosity = 'None' } })
+
+            $xmlResult = $r | ConvertTo-NUnitReport
+
+            # verify against schema
+            $null = $xmlResult.Schemas.Add($null, $schemaPath)
+            $xmlResult.Validate( { throw $args[1].Exception })
+        }
     }
 
     b "Exporting multiple containers" {