Add --mypy-report-style

src/pytest_mypy/__init__.py

@@ -68,10 +68,12 @@ 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_report_style == "mypy":
+        return "\n".join(lines)
+    return "\n".join(line.partition(":")[2].strip() for line in lines)
 
 
 file_error_formatter = default_file_error_formatter
@@ -92,6 +94,16 @@ def pytest_addoption(parser: pytest.Parser) -> None:
         type=str,
         help="adds custom mypy config file",
     )
+    styles = {
+        "mypy": "modify the original mypy output as little as possible",
+        "no-path": "(default) strip the path prefix from mypy errors",
+    }
+    group.addoption(
+        "--mypy-report-style",
+        choices=list(styles),
+        help="change the way mypy output is reported:\n"
+        + "\n".join(f"- {name}: {desc}" for name, desc in styles.items()),
+    )
     group.addoption(
         "--mypy-no-status-check",
         action="store_true",
@@ -175,6 +187,7 @@ def pytest_configure(config: pytest.Config) -> None:
         [
             config.option.mypy,
             config.option.mypy_config_file,
+            config.option.mypy_report_style,
             config.option.mypy_ignore_missing_imports,
             config.option.mypy_no_status_check,
             config.option.mypy_xfail,
@@ -268,13 +281,7 @@ 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

@@ -399,32 +399,27 @@ def pyfunc(x: int) -> str:
     assert result.ret == pytest.ExitCode.TESTS_FAILED
 
 
-def test_api_error_formatter(testdir, xdist_args):
-    """Ensure that the plugin can be configured in a conftest.py."""
+def test_api_file_error_formatter(testdir, xdist_args):
+    """Ensure that the file_error_formatter can be replaced in a conftest.py."""
     testdir.makepyfile(
         bad="""
             def pyfunc(x: int) -> str:
                 return x * 2
         """,
     )
+    file_error = "UnmistakableFileError"
     testdir.makepyfile(
-        conftest="""
-            def custom_file_error_formatter(item, results, errors):
-                return '\\n'.join(
-                    '{path}:{error}'.format(
-                        path=item.fspath,
-                        error=error,
-                    )
-                    for error in errors
-                )
+        conftest=f"""
+            def custom_file_error_formatter(item, results, lines):
+                return '{file_error}'
 
             def pytest_configure(config):
                 plugin = config.pluginmanager.getplugin('mypy')
                 plugin.file_error_formatter = custom_file_error_formatter
         """,
     )
     result = testdir.runpytest_subprocess("--mypy", *xdist_args)
-    result.stdout.fnmatch_lines(["*/bad.py:2: error: Incompatible return value*"])
+    result.stdout.fnmatch_lines([f"*{file_error}*"])
     assert result.ret == pytest.ExitCode.TESTS_FAILED
 
 
@@ -671,3 +666,29 @@ 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_report_style(testdir, xdist_args):
+    """Verify that --mypy-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-report-style", "no-path", *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-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