Disable assertion rewriting external modules

changelog/13403.bugfix.rst

@@ -0,0 +1 @@
+Disable assertion rewriting of external modules

src/_pytest/assertion/__init__.py

@@ -4,6 +4,7 @@
 from __future__ import annotations
 
 from collections.abc import Generator
+import os
 import sys
 from typing import Any
 from typing import TYPE_CHECKING
@@ -108,6 +109,19 @@ def __init__(self, config: Config, mode) -> None:
         self.trace = config.trace.root.get("assertion")
         self.hook: rewrite.AssertionRewritingHook | None = None
 
+    @property
+    def rootpath(self):
+        """
+        Get current root path (current working dir)
+        """
+        try:
+            return os.getcwd()
+        except FileNotFoundError:
+            # Fixes for py's trying to os.getcwd() on py34
+            # when current working directory doesn't exist (previously triggered via xdist only).
+            # Ref: https://github.com/pytest-dev/py/pull/207
+            return os.path.abspath(os.sep)
+
 
 def install_importhook(config: Config) -> rewrite.AssertionRewritingHook:
     """Try to install the rewrite hook, raise SystemError if it fails."""

src/_pytest/assertion/rewrite.py

@@ -238,8 +238,9 @@ def _should_rewrite(self, name: str, fn: str, state: AssertionState) -> bool:
         # modules not passed explicitly on the command line are only
         # rewritten if they match the naming convention for test files
         fn_path = PurePath(fn)
+
         for pat in self.fnpats:
-            if fnmatch_ex(pat, fn_path):
+            if fnmatch_ex(pat, fn_path) and fn_path.is_relative_to(state.rootpath):
                 state.trace(f"matched test file {fn!r}")
                 return True
 

testing/test_assertrewrite.py

@@ -12,6 +12,7 @@
 import inspect
 import marshal
 import os
+from os import mkdir
 from pathlib import Path
 import py_compile
 import re
@@ -22,6 +23,8 @@
 from unittest import mock
 import zipfile
 
+from mock.mock import Mock
+
 import _pytest._code
 from _pytest._io.saferepr import DEFAULT_REPR_MAX_SIZE
 from _pytest.assertion import util
@@ -35,6 +38,7 @@
 from _pytest.assertion.rewrite import rewrite_asserts
 from _pytest.config import Config
 from _pytest.config import ExitCode
+from _pytest.monkeypatch import MonkeyPatch
 from _pytest.pathlib import make_numbered_dir
 from _pytest.pytester import Pytester
 import pytest
@@ -370,6 +374,7 @@ def test_rewrites_plugin_as_a_package(self, pytester: Pytester) -> None:
         pytester.makeconftest('pytest_plugins = ["plugin"]')
         pytester.makepyfile("def test(special_asserter): special_asserter(1, 2)\n")
         result = pytester.runpytest()
+
         result.stdout.fnmatch_lines(["*assert 1 == 2*"])
 
     def test_honors_pep_235(self, pytester: Pytester, monkeypatch) -> None:
@@ -1278,6 +1283,44 @@ def test_meta_path():
         )
         assert pytester.runpytest().ret == 0
 
+    def test_rootpath_base(self, pytester: Pytester, monkeypatch: MonkeyPatch) -> None:
+        """
+        Base cases for get rootpath from AssertionState
+        """
+        from _pytest.assertion import AssertionState
+
+        config = pytester.parseconfig()
+        monkeypatch.chdir(pytester.path)
+        state = AssertionState(config, "rewrite")
+        assert state.rootpath == str(pytester.path)
+        new_rootpath = pytester.path + "/test"
+        if not os.path.exists(new_rootpath):
+            os.mkdir(new_rootpath)
+        monkeypatch.chdir(new_rootpath)
+        state = AssertionState(config, "rewrite")
+        assert state.rootpath == new_rootpath
+
+    @pytest.mark.skipif(
+        sys.platform.startswith("win32"), reason="cannot remove cwd on Windows"
+    )
+    @pytest.mark.skipif(
+        sys.platform.startswith("sunos5"), reason="cannot remove cwd on Solaris"
+    )
+    def test_rootpath_cwd_removed(
+        self, pytester: Pytester, monkeypatch: MonkeyPatch
+    ) -> None:
+        # Setup conditions for py's trying to os.getcwd() on py34
+        # when current working directory doesn't exist (previously triggered via xdist only).
+        # Ref: https://github.com/pytest-dev/py/pull/207
+        from _pytest.assertion import AssertionState
+
+        config = pytester.parseconfig()
+        monkeypatch.setattr(
+            target=os, name="getcwd", value=Mock(side_effect=FileNotFoundError)
+        )
+        state = AssertionState(config, "rewrite")
+        assert state.rootpath == os.path.abspath(os.sep)
+
     def test_write_pyc(self, pytester: Pytester, tmp_path) -> None:
         from _pytest.assertion import AssertionState
         from _pytest.assertion.rewrite import _write_pyc
@@ -1955,6 +1998,76 @@ def test_simple_failure():
             assert hook.find_spec("file") is not None
             assert self.find_spec_calls == ["file"]
 
+    def test_assert_rewrites_only_rootpath(
+        self, pytester: Pytester, hook: AssertionRewritingHook, monkeypatch
+    ) -> None:
+        """
+        If test files contained outside the rootpath, then skip them
+        """
+        pytester.makepyfile(
+            **{
+                "file.py": """\
+                    def test_simple_failure():
+                        assert 1 + 1 == 3
+                """
+            }
+        )
+        with mock.patch.object(hook, "fnpats", ["*.py"]):
+            assert hook.find_spec("file") is not None
+
+        rootpath = f"{os.getcwd()}/tests"
+        if not os.path.exists(rootpath):
+            mkdir(rootpath)
+        monkeypatch.chdir(rootpath)
+        with mock.patch.object(hook, "fnpats", ["*.py"]):
+            assert hook.find_spec("file") is None
+
+    def test_assert_rewrite_correct_for_conftfest(
+        self, pytester: Pytester, hook: AssertionRewritingHook, monkeypatch
+    ) -> None:
+        """
+        Conftest is always rewritten regardless of the root dir
+        """
+        pytester.makeconftest(
+            """
+            import pytest
+            @pytest.fixture
+            def fix(): return 1
+        """
+        )
+
+        rootpath = f"{os.getcwd()}/tests"
+        if not os.path.exists(rootpath):
+            mkdir(rootpath)
+        monkeypatch.chdir(rootpath)
+
+        with mock.patch.object(hook, "fnpats", ["*.py"]):
+            assert hook.find_spec("conftest") is not None
+
+    def test_assert_rewrite_correct_for_plugins(
+        self, pytester: Pytester, hook: AssertionRewritingHook, monkeypatch
+    ) -> None:
+        """
+        Plugins has always been rewritten regardless of the root dir
+        """
+        pkgdir = pytester.mkpydir("plugin")
+        pkgdir.joinpath("__init__.py").write_text(
+            "import pytest\n"
+            "@pytest.fixture\n"
+            "def special_asserter():\n"
+            "    def special_assert(x, y):\n"
+            "        assert x == y\n"
+            "    return special_assert\n",
+            encoding="utf-8",
+        )
+        hook.mark_rewrite("plugin")
+        rootpath = f"{os.getcwd()}/tests"
+        if not os.path.exists(rootpath):
+            mkdir(rootpath)
+        monkeypatch.chdir(rootpath)
+        with mock.patch.object(hook, "fnpats", ["*.py"]):
+            assert hook.find_spec("plugin") is not None
+
     @pytest.mark.skipif(
         sys.platform.startswith("win32"), reason="cannot remove cwd on Windows"
     )