🐛 Change cwd for coverage reports

e2e_projects/mutate_only_covered_lines/pyproject.toml

@@ -16,6 +16,11 @@ dev = [
     "pytest>=8.3.5",
 ]
 
+[tool.coverage.run]
+omit = [
+    "src/mutate_only_covered_lines/omit_me.py",
+]
+
 [tool.mutmut]
 debug = true
 mutate_only_covered_lines = true

e2e_projects/mutate_only_covered_lines/src/mutate_only_covered_lines/__init__.py

@@ -1,3 +1,5 @@
+from mutate_only_covered_lines.omit_me import this_function_shall_NOT_be_mutated
+
 def hello_mutate_only_covered_lines(simple_branch: bool) -> str:
     if simple_branch:
         return "Hello from mutate_only_covered_lines! (true)"
@@ -40,3 +42,6 @@ def mutate_only_covered_lines_multiline(simple_branch: bool) -> str:
         ]
         return f"Hello from mutate_only_covered_lines!" \
             f" (false) {x} {y}"
+
+def do_not_mutate_external_ommited_function():
+    return this_function_shall_NOT_be_mutated()

e2e_projects/mutate_only_covered_lines/src/mutate_only_covered_lines/omit_me.py

@@ -0,0 +1,2 @@
+def this_function_shall_NOT_be_mutated():
+    return 3 + 4

e2e_projects/mutate_only_covered_lines/tests/main/test_mutate_only_covered_lines.py

@@ -1,5 +1,5 @@
 from mutate_only_covered_lines.ignore_me import this_function_shall_NOT_be_mutated
-from mutate_only_covered_lines import hello_mutate_only_covered_lines, mutate_only_covered_lines_multiline, function_with_pragma
+from mutate_only_covered_lines import hello_mutate_only_covered_lines, mutate_only_covered_lines_multiline, function_with_pragma, do_not_mutate_external_ommited_function
 
 """This tests the mutate_only_covered_lines feature."""
 
@@ -14,3 +14,6 @@ def test_mutate_only_covered_lines_multiline():
 
 def call_ignored_function():
     assert this_function_shall_NOT_be_mutated() == 3
+
+def test_do_not_mutate_external_ommited_function():
+    assert do_not_mutate_external_ommited_function() == 7

pyproject.toml

@@ -95,7 +95,6 @@ ignore = [
     "F402",  # import shadowed by loop variable
     "F841",  # local variable assigned but never used
     "UP007", # use X | Y for type annotations
-    "UP038", # use X | Y in isinstance
 ]
 
 [tool.ruff.lint.isort]

src/mutmut/__main__.py

@@ -5,6 +5,7 @@
 import sys
 from collections.abc import Iterable
 from collections.abc import Iterator
+from typing import TYPE_CHECKING
 from typing import Any
 
 from mutmut.type_checking import TypeCheckingError
@@ -64,6 +65,9 @@
 from mutmut.file_mutation import mutate_file_contents
 from mutmut.trampoline_templates import CLASS_NAME_SEPARATOR
 
+if TYPE_CHECKING:
+    from coverage import Coverage
+
 # Document: surviving mutants are retested when you ask mutmut to retest them, interactively in the UI or via command line
 
 # TODO: pragma no mutate should end up in `skipped` category
@@ -540,6 +544,9 @@ def prepare_main_test_run(self) -> None:
     def run_tests(self, *, mutant_name: str | None, tests: Iterable[str]) -> int:
         raise NotImplementedError()
 
+    def collect_main_test_coverage(self, cov: Coverage) -> int:
+        raise NotImplementedError()
+
     def list_all_tests(self) -> ListAllTestsResult:
         raise NotImplementedError()
 
@@ -607,6 +614,14 @@ def execute_pytest(self, params: list[str], **kwargs: Any) -> int:
             raise BadTestExecutionCommandsException(params)
         return exit_code
 
+    def _pytest_args_regular_run(self, tests: Iterable[str]) -> list[str]:
+        pytest_args = ["-x", "-q", "-p", "no:randomly", "-p", "no:random-order"]
+        if tests:
+            pytest_args += list(tests)
+        else:
+            pytest_args += self._pytest_add_cli_args_test_selection
+        return pytest_args
+
     def run_stats(self, *, tests: Iterable[str]) -> int:
         class StatsCollector:
             # noinspection PyMethodMayBeStatic
@@ -626,27 +641,20 @@ def pytest_runtest_makereport(self, item: Any, call: Any) -> None:
 
         stats_collector = StatsCollector()
 
-        pytest_args = ["-x", "-q"]
-        if tests:
-            pytest_args += list(tests)
-        else:
-            pytest_args += self._pytest_add_cli_args_test_selection
         with change_cwd("mutants"):
-            return int(self.execute_pytest(pytest_args, plugins=[stats_collector]))
+            return int(self.execute_pytest(self._pytest_args_regular_run(tests), plugins=[stats_collector]))
 
     def run_tests(self, *, mutant_name: str | None, tests: Iterable[str]) -> int:
-        pytest_args = ["-x", "-q", "-p", "no:randomly", "-p", "no:random-order"]
-        if tests:
-            pytest_args += list(tests)
-        else:
-            pytest_args += self._pytest_add_cli_args_test_selection
         with change_cwd("mutants"):
-            return int(self.execute_pytest(pytest_args))
+            return int(self.execute_pytest(self._pytest_args_regular_run(tests)))
+
+    def collect_main_test_coverage(self, cov: Coverage) -> int:
+        with change_cwd("mutants"), cov.collect():
+            self.prepare_main_test_run()
+            return int(self.execute_pytest(self._pytest_args_regular_run([])))
 
     def run_forced_fail(self) -> int:
-        pytest_args = ["-x", "-q"] + self._pytest_add_cli_args_test_selection
-        with change_cwd("mutants"):
-            return int(self.execute_pytest(pytest_args))
+        return self.run_tests(mutant_name=None, tests=[])
 
     def list_all_tests(self) -> ListAllTestsResult:
         class TestsCollector:
@@ -977,6 +985,7 @@ def load_config() -> Config:
             Path("setup.cfg"),
             Path("pyproject.toml"),
             Path("pytest.ini"),
+            Path(".coveragerc"),
             Path(".gitignore"),
         ]
         + list(Path(".").glob("test*.py")),

src/mutmut/code_coverage.py

@@ -41,10 +41,8 @@ def gather_coverage(runner: TestRunner, source_files: Iterable[Path]) -> dict[st
     mutants_path = Path("mutants")
 
     # Run the tests and gather coverage
-    cov = coverage.Coverage(source=[str(mutants_path.absolute())], data_file=None)
-    with cov.collect():
-        runner.prepare_main_test_run()
-        runner.run_tests(mutant_name=None, tests=[])
+    cov = coverage.Coverage(data_file=None)
+    runner.collect_main_test_coverage(cov)
 
     # Build mapping of filenames to covered lines
     # The CoverageData object is a wrapper around sqlite, and this

tests/e2e/test_e2e_coverage.py

@@ -42,6 +42,7 @@ def test_mutate_only_covered_lines_result_snapshot():
                 "mutate_only_covered_lines.x_mutate_only_covered_lines_multiline__mutmut_30": 1,
                 "mutate_only_covered_lines.x_mutate_only_covered_lines_multiline__mutmut_31": 1,
                 "mutate_only_covered_lines.x_mutate_only_covered_lines_multiline__mutmut_32": 1,
-            }
+            },
+            "mutants/src/mutate_only_covered_lines/omit_me.py.meta": {},
         }
     )