fix: port collocated tests pattern matching from main

When tests_root overlaps module_root (common in JS monorepos), use
filename pattern matching instead of directory-based filtering to avoid
excluding all source files.

Author: KRRT7

codeflash/discovery/functions_to_optimize.py

@@ -868,13 +868,36 @@ def is_test_file(file_path_normalized: str) -> bool:
     return {k: v for k, v in filtered_modified_functions.items() if v}, functions_count
 
 
+def _is_test_file_by_pattern(file_path: Path) -> bool:
+    """Check if a file is a test file using naming conventions.
+
+    Used when tests_root overlaps with module_root, so directory-based filtering would
+    incorrectly exclude all source files. Falls back to filename and directory patterns.
+    """
+    name = file_path.name.lower()
+    if name.startswith("test_") or name == "conftest.py":
+        return True
+    test_name_patterns = (".test.", ".spec.", "_test.", "_spec.")
+    if any(p in name for p in test_name_patterns):
+        return True
+    path_str = str(file_path).lower()
+    test_dir_patterns = (os.sep + "test" + os.sep, os.sep + "tests" + os.sep, os.sep + "__tests__" + os.sep)
+    return any(p in path_str for p in test_dir_patterns)
+
+
 def filter_files_optimized(file_path: Path, tests_root: Path, ignore_paths: list[Path], module_root: Path) -> bool:
     """Optimized version of the filter_functions function above.
 
     Takes in file paths and returns the count of files that are to be optimized.
     """
     submodule_paths = None
-    if file_path.is_relative_to(tests_root):
+    # When tests_root overlaps module_root (e.g., both are "src"), use pattern matching
+    # instead of directory matching to avoid filtering out all source files.
+    tests_root_overlaps = tests_root == module_root or module_root.is_relative_to(tests_root)
+    if tests_root_overlaps:
+        if _is_test_file_by_pattern(file_path):
+            return False
+    elif file_path.is_relative_to(tests_root):
         return False
     if file_path in ignore_paths or any(file_path.is_relative_to(ignore_path) for ignore_path in ignore_paths):
         return False