Add --mypy-default-report-style

Author: dmtucker

src/pytest_mypy/__init__.py

@@ -68,10 +68,13 @@ def default_test_name_formatter(*, item: MypyFileItem) -> str:
 def default_file_error_formatter(
     item: MypyItem,
     results: MypyResults,
-    errors: List[str],
+    lines: List[str],
 ) -> str:
     """Create a string to be displayed when mypy finds errors in a file."""
-    return "\n".join(errors)
+    if item.config.option.mypy_default_report_style == "mypy":
+        return "\n".join(lines)
+    # "pytest" style
+    return "\n".join(line.partition(":")[2].strip() for line in lines)
 
 
 file_error_formatter = default_file_error_formatter
@@ -92,6 +95,14 @@ def pytest_addoption(parser: pytest.Parser) -> None:
         type=str,
         help="adds custom mypy config file",
     )
+    group.addoption(
+        "--mypy-default-report-style",
+        choices=[
+            "mypy",
+            "pytest",
+        ],
+        help="change the way mypy output is reported",
+    )
     group.addoption(
         "--mypy-no-status-check",
         action="store_true",
@@ -175,6 +186,7 @@ def pytest_configure(config: pytest.Config) -> None:
         [
             config.option.mypy,
             config.option.mypy_config_file,
+            config.option.mypy_default_report_style,
             config.option.mypy_ignore_missing_imports,
             config.option.mypy_no_status_check,
             config.option.mypy_xfail,
@@ -268,13 +280,7 @@ def runtest(self) -> None:
                         reason="mypy errors are expected by --mypy-xfail.",
                     )
                 )
-            raise MypyError(
-                file_error_formatter(
-                    self,
-                    results,
-                    errors=[line.partition(":")[2].strip() for line in lines],
-                )
-            )
+            raise MypyError(file_error_formatter(self, results, lines))
 
     def reportinfo(self) -> Tuple[Path, None, str]:
         """Produce a heading for the test report."""

tests/test_pytest_mypy.py

@@ -410,7 +410,7 @@ def pyfunc(x: int) -> str:
     file_error = "UnmistakableFileError"
     testdir.makepyfile(
         conftest=f"""
-            def custom_file_error_formatter(item, results, errors):
+            def custom_file_error_formatter(item, results, lines):
                 return '{file_error}'
 
             def pytest_configure(config):
@@ -666,3 +666,33 @@ def pytest_configure(config):
 def test_error_severity():
     """Verify that non-error lines produce no severity."""
     assert pytest_mypy._error_severity("arbitrary line with no error") is None
+
+
+def test_mypy_default_report_style(testdir, xdist_args):
+    """Verify that --mypy-default-report-style functions correctly."""
+    module_name = "unmistakable_module_name"
+    testdir.makepyfile(
+        **{
+            module_name: """
+            def pyfunc(x: int) -> str:
+                return x * 2
+        """
+        },
+    )
+    result = testdir.runpytest_subprocess(
+        "--mypy-default-report-style", "pytest", *xdist_args
+    )
+    mypy_file_checks = 1
+    mypy_status_check = 1
+    mypy_checks = mypy_file_checks + mypy_status_check
+    result.assert_outcomes(failed=mypy_checks)
+    result.stdout.fnmatch_lines(["2: error: Incompatible return value*"])
+    assert result.ret == pytest.ExitCode.TESTS_FAILED
+    result = testdir.runpytest_subprocess(
+        "--mypy-default-report-style", "mypy", *xdist_args
+    )
+    result.assert_outcomes(failed=mypy_checks)
+    result.stdout.fnmatch_lines(
+        [f"{module_name}.py:2: error: Incompatible return value*"]
+    )
+    assert result.ret == pytest.ExitCode.TESTS_FAILED