Fix CI failure: Add properly structured tests directory and basic units

tests/__init__.py

@@ -0,0 +1 @@
+# Making tests a package

tests/test_transpose.py

@@ -0,0 +1,38 @@
+import unittest
+from transpose_chords import transpose_note, transpose_chord, transpose_text
+
+class TestTranspose(unittest.TestCase):
+    def test_transpose_note_sharps(self):
+        self.assertEqual(transpose_note('C', 1), 'Db')
+        self.assertEqual(transpose_note('C#', 1), 'D')
+        self.assertEqual(transpose_note('E', 1), 'F')
+        self.assertEqual(transpose_note('B', 1), 'C')
+
+    def test_transpose_note_flats(self):
+        self.assertEqual(transpose_note('Db', 1), 'D')
+        self.assertEqual(transpose_note('Eb', 1), 'E')
+        self.assertEqual(transpose_note('Bb', 2), 'C')
+
+    def test_transpose_chord_simple(self):
+        self.assertEqual(transpose_chord('C', 2), 'D')
+        self.assertEqual(transpose_chord('Am7', 1), 'Bbm7')
+        self.assertEqual(transpose_chord('Gmaj7', 3), 'Bbmaj7')
+
+    def test_transpose_chord_slash(self):
+        # transpose_chord handles single chords. 
+        # Slash chords are handled in transpose_text by splitting.
+        self.assertEqual(transpose_chord('C', 1), 'Db')
+        self.assertEqual(transpose_chord('G', 1), 'Ab')
+
+    def test_transpose_text_song(self):
+        song = "[C]Hello [G/B]World\n[Am7]Testing"
+        expected = "[Db]Hello [Ab/C]World\n[Bbm7]Testing"
+        self.assertEqual(transpose_text(song, 1), expected)
+
+    def test_smart_notes(self):
+        # Verify the SMART_NOTES mapping
+        self.assertEqual(transpose_note('G', 1), 'Ab')
+        self.assertEqual(transpose_note('G#', 1), 'A')
+
+if __name__ == '__main__':
+    unittest.main()

tests/test_utils.py

@@ -0,0 +1,13 @@
+import unittest
+from utils import slugify
+
+class TestUtils(unittest.TestCase):
+    def test_slugify(self):
+        self.assertEqual(slugify("Hello World"), "hello-world")
+        self.assertEqual(slugify("Song! @# Title"), "song-title")
+        self.assertEqual(slugify("  Trim Me  "), "trim-me")
+        self.assertEqual(slugify(""), "chord-sheet")
+        self.assertEqual(slugify(None), "chord-sheet")
+
+if __name__ == '__main__':
+    unittest.main()