Enable branch code coverage

Author: dmtucker

src/pytest_mypy.py

@@ -16,6 +16,7 @@
 PYTEST_MAJOR_VERSION = int(pytest.__version__.partition(".")[0])
 mypy_argv = []
 nodeid_name = "mypy"
+terminal_summary_title = "mypy"
 
 
 def default_file_error_formatter(item, results, errors):
@@ -205,8 +206,7 @@ def runtest(self):
                 for error in errors
             ):
                 raise MypyError(file_error_formatter(self, results, errors))
-            # This line cannot be easily covered on mypy < 0.990:
-            warnings.warn("\n" + "\n".join(errors), MypyWarning)  # pragma: no cover
+            warnings.warn("\n" + "\n".join(errors), MypyWarning)
 
     def reportinfo(self):
         """Produce a heading for the test report."""
@@ -258,7 +258,9 @@ def from_mypy(
     ) -> "MypyResults":
         """Generate results from mypy."""
 
-        if opts is None:
+        # This is covered by test_mypy_results_from_mypy_with_opts;
+        # however, coverage is not recognized on py38-pytest4.6:
+        if opts is None:  # pragma: no cover
             opts = mypy_argv[:]
         abspath_errors = {
             os.path.abspath(str(item.fspath)): [] for item in items
@@ -322,18 +324,20 @@ class MypyWarning(pytest.PytestWarning):
 
 def pytest_terminal_summary(terminalreporter, config):
     """Report stderr and unrecognized lines from stdout."""
-    if _is_master(config):
-        try:
-            with open(config._mypy_results_path, mode="r") as results_f:
-                results = MypyResults.load(results_f)
-        except FileNotFoundError:
-            # No MypyItems executed.
-            return
-        if results.unmatched_stdout or results.stderr:
-            terminalreporter.section("mypy")
-            if results.unmatched_stdout:
-                color = {"red": True} if results.status else {"green": True}
-                terminalreporter.write_line(results.unmatched_stdout, **color)
-            if results.stderr:
-                terminalreporter.write_line(results.stderr, yellow=True)
-        os.remove(config._mypy_results_path)
+    if not _is_master(config):
+        # This isn't hit in pytest 5.0 for some reason.
+        return  # pragma: no cover
+    try:
+        with open(config._mypy_results_path, mode="r") as results_f:
+            results = MypyResults.load(results_f)
+    except FileNotFoundError:
+        # No MypyItems executed.
+        return
+    if results.unmatched_stdout or results.stderr:
+        terminalreporter.section(terminal_summary_title)
+        if results.unmatched_stdout:
+            color = {"red": True} if results.status else {"green": True}
+            terminalreporter.write_line(results.unmatched_stdout, **color)
+        if results.stderr:
+            terminalreporter.write_line(results.stderr, yellow=True)
+    os.remove(config._mypy_results_path)

tests/test_pytest_mypy.py

@@ -1,14 +1,27 @@
 import signal
+import sys
 import textwrap
 
 import mypy.version
 from packaging.version import Version
 import pexpect
 import pytest
 
+import pytest_mypy
+
 
 MYPY_VERSION = Version(mypy.version.__version__)
 PYTEST_VERSION = Version(pytest.__version__)
+PYTHON_VERSION = Version(
+    ".".join(
+        str(token)
+        for token in [
+            sys.version_info.major,
+            sys.version_info.minor,
+            sys.version_info.micro,
+        ]
+    )
+)
 
 
 @pytest.fixture(
@@ -100,7 +113,7 @@ def pyfunc(x: int) -> str:
     assert "_mypy_results_path" not in result.stderr.str()
 
 
-def test_mypy_annotation_unchecked(testdir, xdist_args):
+def test_mypy_annotation_unchecked(testdir, xdist_args, tmp_path, monkeypatch):
     """Verify that annotation-unchecked warnings do not manifest as an error."""
     testdir.makepyfile(
         """
@@ -109,6 +122,29 @@ def pyfunc(x):
                 return x * y
         """,
     )
+    min_mypy_version = Version("0.990")
+    if MYPY_VERSION < min_mypy_version:
+        # mypy doesn't emit annotation-unchecked warnings until 0.990:
+        fake_mypy_path = tmp_path / "mypy"
+        fake_mypy_path.mkdir()
+        (fake_mypy_path / "__init__.py").touch()
+        (fake_mypy_path / "api.py").write_text(
+            textwrap.dedent(
+                """
+                    def run(*args, **kwargs):
+                        return (
+                            "test_mypy_annotation_unchecked.py:2:"
+                            " note: By default the bodies of untyped functions"
+                            " are not checked, consider using --check-untyped-defs"
+                            "  [annotation-unchecked]\\nSuccess: no issues found in"
+                            " 1 source file\\n",
+                            "",
+                            0,
+                        )
+                """
+            )
+        )
+        monkeypatch.setenv("PYTHONPATH", str(tmp_path))
     result = testdir.runpytest_subprocess(*xdist_args)
     result.assert_outcomes()
     result = testdir.runpytest_subprocess("--mypy", *xdist_args)
@@ -552,3 +588,68 @@ def test_mypy_item_collect(request):
     mypy_status_check = 1
     result.assert_outcomes(passed=test_count + mypy_file_checks + mypy_status_check)
     assert result.ret == 0
+
+
+@pytest.mark.xfail(
+    MYPY_VERSION < Version("0.750"),
+    raises=AssertionError,
+    reason="https://github.com/python/mypy/issues/7800",
+)
+def test_mypy_results_from_mypy_with_opts():
+    """MypyResults.from_mypy respects passed options."""
+    mypy_results = pytest_mypy.MypyResults.from_mypy([], opts=["--version"])
+    assert mypy_results.status == 0
+    assert mypy_results.abspath_errors == {}
+    assert str(MYPY_VERSION) in mypy_results.stdout
+
+
+@pytest.mark.xfail(
+    Version("3.7") < PYTHON_VERSION < Version("3.9")
+    and Version("0.710") <= MYPY_VERSION < Version("0.720"),
+    raises=AssertionError,
+    reason="Mypy crashes for some reason.",
+)
+def test_mypy_no_output(testdir, xdist_args):
+    """No terminal summary is shown if there is no output from mypy."""
+    type_ignore = (
+        "# type: ignore"
+        if (
+            PYTEST_VERSION
+            < Version("6.0")  # Pytest didn't add type annotations until 6.0.
+            or MYPY_VERSION < Version("0.710")
+        )
+        else ""
+    )
+    testdir.makepyfile(
+        # Mypy prints a success message to stderr by default:
+        # "Success: no issues found in 1 source file"
+        # Clear stderr and unmatched_stdout to simulate mypy having no output:
+        conftest=f"""
+            import pytest  {type_ignore}
+
+            @pytest.hookimpl(hookwrapper=True)
+            def pytest_terminal_summary(config):
+                mypy_results_path = getattr(config, "_mypy_results_path", None)
+                if not mypy_results_path:
+                    # xdist worker
+                    return
+                pytest_mypy = config.pluginmanager.getplugin("mypy")
+                with open(mypy_results_path, mode="w") as results_f:
+                    pytest_mypy.MypyResults(
+                        opts=[],
+                        stdout="",
+                        stderr="",
+                        status=0,
+                        abspath_errors={{}},
+                        unmatched_stdout="",
+                    ).dump(results_f)
+                yield
+        """,
+    )
+    result = testdir.runpytest_subprocess("--mypy", *xdist_args)
+    mypy_file_checks = 1
+    mypy_status_check = 1
+    mypy_checks = mypy_file_checks + mypy_status_check
+    result.assert_outcomes(passed=mypy_checks)
+    assert result.ret == 0
+    assert f"= {pytest_mypy.terminal_summary_title} =" not in str(result.stdout)

tox.ini

@@ -44,11 +44,11 @@ deps =
 
     packaging ~= 21.3
     pexpect ~= 4.8.0
-    pytest-cov ~= 2.10
+    pytest-cov ~= 4.1.0
     pytest-randomly ~= 3.4
     pytest-xdist ~= 1.34
 
-commands = pytest -p no:mypy {posargs:--cov pytest_mypy --cov-fail-under 100 --cov-report term-missing -n auto}
+commands = pytest -p no:mypy {posargs:--cov pytest_mypy --cov-branch --cov-fail-under 100 --cov-report term-missing -n auto}
 
 [pytest]
 testpaths = tests