More precise checking for warning source (#5506)

GitOrigin-RevId: becd5a9c50a9492e5206cd3616626c76a480b0b3

python/pathway/tests/test_common.py

@@ -3463,13 +3463,14 @@ def test_update_cells_0_rows():
         """
     )
 
-    with warns_here(
-        match=re.escape(
-            "Key sets of self and other in update_cells are the same. "
-            "Using with_columns instead of update_cells."
-        ),
-    ):
+    match = re.escape(
+        "Key sets of self and other in update_cells are the same. "
+        "Using with_columns instead of update_cells."
+    )
+
+    with warns_here(match=match):
         new = old.update_cells(update)
+    with warns_here(match=match):
         new2 = old << update
     assert_table_equality(new, expected)
     assert_table_equality(new2, expected)

python/pathway/tests/utils.py

@@ -509,10 +509,27 @@ def warns_here(
     with pytest.warns(expected_warning, match=match) as context:
         yield context
 
-    for warning in context:
-        assert warning.filename == file_name
-        assert warning.lineno >= first_line
-        assert warning.lineno in function_lines
+    def matches(warning) -> bool:
+        if not isinstance(warning.message, expected_warning):
+            return False
+        if match is not None and not re.search(match, str(warning.message)):
+            return False
+        if warning.filename != file_name:
+            return False
+        if warning.lineno < first_line:
+            return False
+        if warning.lineno not in function_lines:
+            return False
+        return True
+
+    if not any(matches(warning) for warning in context):
+        raise AssertionError(
+            "No matched warning caused by expected source line.\n"
+            "All warnings:\n"
+            + "\n".join(f"  {warning}" for warning in context)
+            + f"\nExpected: {file_name!r}, line in "
+            f"{list(line for line in function_lines if line >= first_line)}"
+        )
 
 
 def deprecated_call_here(