test: config mutmut

mutmut_config.py

@@ -1,4 +1,27 @@
+import os.path
+
+
 def pre_mutation(context):
     line = context.current_source_line.strip()
-    if line.strip().startswith(("assert False", "@overload", "= TypeVar")):
+    if line.startswith(("assert False", "@overload")):
         context.skip = True
+
+    if "= TypeVar" in line:
+        context.skip = True
+
+    return
+    """Extract the coverage contexts if possible and only run the tests
+    matching this data."""
+    if not context.config.coverage_data:
+        # mutmut was run without ``--use-coverage``
+        return
+    fname = os.path.abspath(context.filename)
+    contexts_for_file = context.config.coverage_data.get(fname, {})
+    contexts_for_line = contexts_for_file.get(context.current_line_index, [])
+    print(line)
+    print(contexts_for_line)
+
+    context.config.test_command += " ".join(
+        repr(arg) for arg in contexts_for_line if arg
+    )
+    print(context.config.test_command)

noxfile.py

@@ -49,4 +49,20 @@ def docs(session):
 def mutmut(session):
     session.install("poetry")
     session.run("poetry", "install", "--with=dev")
+
+    coverage = False
+
+    if coverage:
+        session.run("coverage", "erase")
+
+        session.env["COVERAGE_PROCESS_START"] = str(
+            Path(__file__).parent / "pyproject.toml"
+        )
+        session.env["TOP"] = str(Path(__file__).parent)
+        session.run("pytest", "--doctest-modules", "inline_snapshot", "tests")
+        session.run("coverage", "combine")
+
     session.run("mutmut", "run", *session.posargs)
+
+    if coverage:
+        session.run("coverage", "erase")

pyproject.toml

@@ -12,6 +12,9 @@ version_files = [
 ]
 version_provider = "poetry"
 
+[tool.coverage.html]
+show_contexts = true
+
 [tool.coverage.report]
 exclude_lines = ["pragma: no cover", "assert False", "raise NotImplemented", "\\.\\.\\."]
 

tests/conftest.py

@@ -1 +1,20 @@
 pytest_plugins = "pytester"
+
+import pytest
+import coverage
+
+import os
+
+ctx_key = "COVERAGE_CONTEXT"
+
+
+@pytest.fixture(autouse=True)
+def coverage_context(request):
+    ctx = request.node.nodeid
+    coverage.Coverage.current().switch_context(request.node.nodeid)
+
+    os.environ[ctx_key] = ctx
+
+    yield
+
+    coverage.Coverage.current().switch_context("")