fix(ci): make pyrefly diff comments focus on diagnostics (#32778)

api/tests/unit_tests/libs/test_pyrefly_diagnostics.py

@@ -0,0 +1,51 @@
+from libs.pyrefly_diagnostics import extract_diagnostics
+
+
+def test_extract_diagnostics_keeps_only_summary_and_location_lines() -> None:
+    # Arrange
+    raw_output = """INFO Checking project configured at `/tmp/project/pyrefly.toml`
+ERROR `result` may be uninitialized [unbound-name]
+   --> controllers/console/app/annotation.py:126:16
+    |
+126 |         return result, 200
+    |                ^^^^^^
+    |
+ERROR Object of class `App` has no attribute `access_mode` [missing-attribute]
+   --> controllers/console/app/app.py:574:13
+    |
+574 |             app_model.access_mode = app_setting.access_mode
+    |             ^^^^^^^^^^^^^^^^^^^^^
+"""
+
+    # Act
+    diagnostics = extract_diagnostics(raw_output)
+
+    # Assert
+    assert diagnostics == (
+        "ERROR `result` may be uninitialized [unbound-name]\n"
+        "   --> controllers/console/app/annotation.py:126:16\n"
+        "ERROR Object of class `App` has no attribute `access_mode` [missing-attribute]\n"
+        "   --> controllers/console/app/app.py:574:13\n"
+    )
+
+
+def test_extract_diagnostics_handles_error_without_location_line() -> None:
+    # Arrange
+    raw_output = "ERROR unexpected pyrefly output format [bad-format]\n"
+
+    # Act
+    diagnostics = extract_diagnostics(raw_output)
+
+    # Assert
+    assert diagnostics == "ERROR unexpected pyrefly output format [bad-format]\n"
+
+
+def test_extract_diagnostics_returns_empty_for_non_error_output() -> None:
+    # Arrange
+    raw_output = "INFO Checking project configured at `/tmp/project/pyrefly.toml`\n"
+
+    # Act
+    diagnostics = extract_diagnostics(raw_output)
+
+    # Assert
+    assert diagnostics == ""