Merge pull request #374 from Otto-AA/libcst

Use LibCST instead of parso

Author: boxed

.gitignore

@@ -1,3 +1,6 @@
+# Mutant files
+e2e_projects/**/mutants
+
 *.py[cod]
 examples/db.sqlite3
 venv

CONTRIBUTING.rst

@@ -19,6 +19,10 @@ Running the tests
 
     pytest
 
+This also runs E2E tests that verify that `mutmut run` produces the same output as before. If your code changes should change the output of `mutmut run` and this test fails, try to delete the `snapshots/*.json` files (as described in the test errors).
+
+If pytest terminates before reporting the test failures, it likely hit a case where mutmut calls `os._exit(...)`. Try looking at these calls first for troubleshooting.
+
 Running your local version of Mutmut against a test codebase
 ------------------------------------------------------------
 

e2e_projects/my_lib/README.md

@@ -0,0 +1 @@
+This project will be E2E tested. It mainly serves as a "canary" that alerts you when code changes affect which mutants survive.

e2e_projects/my_lib/pyproject.toml

@@ -0,0 +1,20 @@
+[project]
+name = "my-lib"
+version = "0.1.0"
+description = "Add your description here"
+readme = "README.md"
+authors = []
+requires-python = ">=3.10"
+dependencies = []
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[dependency-groups]
+dev = [
+    "pytest>=8.3.5",
+]
+
+[tool.mutmut]
+debug = true

e2e_projects/my_lib/src/my_lib/__init__.py

@@ -0,0 +1,60 @@
+from collections.abc import Callable
+from functools import cache
+from typing import Union
+
+
+def hello() -> str:
+    return "Hello from my-lib!"
+
+def badly_tested() -> str:
+    return "Mutants for this method should survive"
+
+def untested() -> str:
+    return "Mutants for this method should survive"
+
+def make_greeter(name: Union[str, None]) -> Callable[[], str]:
+    def hi():
+        if name:
+            return "Hi " + name
+        else:
+            return "Hey there!"
+
+    return hi
+
+def fibonacci(n: int) -> int:
+    if n <= 1:
+        return n
+    return fibonacci(n - 1) + fibonacci(n - 2)
+
+@cache
+def cached_fibonacci(n: int) -> int:
+    if n <= 1:
+        return n
+    return fibonacci(n - 1) + fibonacci(n - 2)
+
+class Point:
+    def __init__(self, x: int, y: int) -> None:
+        self.x = x
+        self.y = y
+
+    def abs(self) -> 'Point':
+        return Point(abs(self.x), abs(self.y))
+
+    def add(self, other: 'Point'):
+        self.x += other.x
+        self.y += other.y
+
+    def to_origin(self):
+        self.x = 0
+        self.y = 0
+
+    def ignored(self):
+        self.foo = 'bar' # pragma: no mutate
+
+    @staticmethod
+    def from_coords(coords) -> 'Point':
+        return Point(coords[0], coords[1])
+
+    @property
+    def coords(self):
+        return self.x, self.y

e2e_projects/my_lib/tests/test_my_lib.py

@@ -0,0 +1,33 @@
+from my_lib import hello, Point, badly_tested, make_greeter, fibonacci, cached_fibonacci
+
+"""These tests are flawed on purpose, some mutants survive and some are killed."""
+
+def test_hello():
+    assert hello() == 'Hello from my-lib!'
+
+def test_badly_tested():
+    assert badly_tested()
+
+def test_greeter():
+    greet = make_greeter("mut")
+    assert greet() == "Hi mut"
+
+def test_point():
+    p = Point(0, 1)
+    p.add(Point(1, 0))
+
+    assert p.x == 1
+    assert p.y == 1
+
+    p.to_origin()
+
+    assert p.x == 0
+
+    assert isinstance(p.coords, tuple)
+
+def test_point_from_coords():
+    assert Point.from_coords((1, 2)).x == 1
+
+def test_fibonacci():
+    assert fibonacci(1) == 1
+    assert cached_fibonacci(1) == 1