test: Add comprehensive test for get_file_mentions with various formats

tests/basic/test_coder.py

@@ -285,6 +285,80 @@ class TestCoder(unittest.TestCase):
 
             self.assertEqual(coder.abs_fnames, set([str(fname.resolve())]))
             
+    def test_get_file_mentions_various_formats(self):
+        with GitTemporaryDirectory():
+            io = InputOutput(pretty=False, yes=True)
+            coder = Coder.create(self.GPT35, None, io)
+            
+            # Create test files
+            test_files = [
+                "file1.txt",
+                "file2.py",
+                "dir/nested_file.js",
+                "dir/subdir/deep_file.html",
+                "file with spaces.txt",
+                "special_chars!@#.md",
+            ]
+            
+            for fname in test_files:
+                fpath = Path(fname)
+                fpath.parent.mkdir(parents=True, exist_ok=True)
+                fpath.touch()
+            
+            # Mock get_addable_relative_files to return our test files
+            coder.get_addable_relative_files = MagicMock(return_value=set(test_files))
+            
+            # Test different mention formats
+            test_cases = [
+                # Simple plain text mentions
+                (f"You should edit {test_files[0]} first", {test_files[0]}),
+                
+                # Multiple files in plain text
+                (f"Edit both {test_files[0]} and {test_files[1]}", {test_files[0], test_files[1]}),
+                
+                # Files in backticks
+                (f"Check the file `{test_files[2]}`", {test_files[2]}),
+                
+                # Files in code blocks
+                (f"```\n{test_files[3]}\n```", {test_files[3]}),
+                
+                # Files in code blocks with language specifier
+                (f"```python\nwith open('{test_files[1]}', 'r') as f:\n    data = f.read()\n```", {test_files[1]}),
+                
+                # Files with Windows-style paths
+                (f"Edit the file {test_files[2].replace('/', '\\')}", {test_files[2]}),
+                
+                # Files with spaces
+                (f"Look at '{test_files[4]}'", {test_files[4]}),
+                
+                # Files with different quote styles
+                (f'Check "{test_files[5]}" now', {test_files[5]}),
+                
+                # Files mentioned in markdown links
+                (f"See the file [{test_files[0]}]({test_files[0]})", {test_files[0]}),
+                
+                # All files in one complex message
+                (
+                    f"First, edit `{test_files[0]}`. Then modify {test_files[1]}.\n"
+                    f"```js\n// Update this file\nconst file = '{test_files[2]}';\n```\n"
+                    f"Finally check {test_files[3].replace('/', '\\')}",
+                    {test_files[0], test_files[1], test_files[2], test_files[3]}
+                ),
+                
+                # Mention with SEARCH/REPLACE format
+                (
+                    f"{test_files[1]}\n````python\n<<<<<<< SEARCH\ndef old_function():\n    pass\n=======\n"
+                    f"def new_function():\n    return True\n>>>>>>> REPLACE\n````",
+                    {test_files[1]}
+                ),
+            ]
+            
+            for content, expected_mentions in test_cases:
+                with self.subTest(content=content):
+                    mentioned_files = coder.get_file_mentions(content)
+                    self.assertEqual(mentioned_files, expected_mentions, 
+                                     f"Failed to extract mentions from: {content}")
+
     def test_get_file_mentions_path_formats(self):
         with GitTemporaryDirectory():
             io = InputOutput(pretty=False, yes=True)