1 files changed, 54 insertions, 0 deletions
diff --git a/tests/fix_mypy.py b/tests/fix_mypy.py
new file mode 100644
index 0000000..b860a32
--- /dev/null
+++ b/tests/fix_mypy.py
@@ -0,0 +1,54 @@
+import re
+import subprocess as sp
+
+import pytest
+
+
+def pytest_configure(config):
+    config.addinivalue_line(
+        "markers",
+        "mypy: the test uses mypy (the marker is set automatically"
+        " on tests using the fixture)",
+    )
+
+
+def pytest_collection_modifyitems(items):
+    for item in items:
+        if "mypy" in item.fixturenames:
+            # add a mypy tag so we can address these tests only
+            item.add_marker(pytest.mark.mypy)
+
+            # All the tests using mypy are slow
+            item.add_marker(pytest.mark.slow)
+
+
+@pytest.fixture(scope="session")
+def mypy(tmp_path_factory):
+    cache_dir = tmp_path_factory.mktemp(basename="mypy_cache")
+    src_dir = tmp_path_factory.mktemp("source")
+
+    class MypyRunner:
+        def run_on_file(self, filename):
+            cmdline = f"""
+                mypy
+                --strict
+                --show-error-codes --no-color-output --no-error-summary
+                --config-file= --cache-dir={cache_dir}
+                """.split()
+            cmdline.append(filename)
+            return sp.run(cmdline, stdout=sp.PIPE, stderr=sp.STDOUT)
+
+        def run_on_source(self, source):
+            fn = src_dir / "tmp.py"
+            with fn.open("w") as f:
+                f.write(source)
+
+            return self.run_on_file(str(fn))
+
+        def get_revealed(self, line):
+            """return the type from an output of reveal_type"""
+            return re.sub(
+                r".*Revealed type is (['\"])([^']+)\1.*", r"\2", line
+            ).replace("*", "")
+
+    return MypyRunner()