Fixed --pyargs not finding modules in the current directory when running pytest from a subdirectory

changelog/14048.bugfix.rst

@@ -0,0 +1,3 @@
+Fixed ``--pyargs`` not finding modules in the current directory when running pytest from a subdirectory, particularly when using tox.
+
+The invocation directory is now added to ``sys.path`` early during initialization when ``--pyargs`` is used, ensuring that ``importlib.util.find_spec()`` can locate modules in the current working directory.

src/_pytest/config/__init__.py

@@ -1274,6 +1274,14 @@ def pytest_load_initial_conftests(self, early_config: Config) -> None:
         # early_config.args it not set yet. But we need it for
         # discovering the initial conftests. So "pre-run" the logic here.
         # It will be done for real in `parse()`.
+
+        # When using --pyargs, ensure invocation_dir is in sys.path so that
+        # modules in the current directory can be found by importlib.
+        if early_config.known_args_namespace.pyargs:
+            invocation_dir_str = str(early_config.invocation_params.dir)
+            if invocation_dir_str not in sys.path:
+                sys.path.insert(0, invocation_dir_str)
+
         args, _args_source = early_config._decide_args(
             args=early_config.known_args_namespace.file_or_dir,
             pyargs=early_config.known_args_namespace.pyargs,

testing/acceptance_test.py

@@ -690,6 +690,27 @@ def test_pyargs_filename_looks_like_module(self, pytester: Pytester) -> None:
         result = pytester.runpytest("--pyargs", "t.py")
         assert result.ret == ExitCode.OK
 
+    def test_pyargs_finds_module_in_current_dir(self, pytester: Pytester) -> None:
+        """Regression test for issue #14048.
+
+        Test that --pyargs can find modules in the current directory
+        (invocation directory) even when pytest's rootdir is different.
+        This is important for tox usage where pytest is run from a subdirectory.
+        """
+        # Create a module structure in the current directory
+        pkg = pytester.mkpydir("amodule")
+        tests_pkg = pkg / "tests"
+        tests_pkg.mkdir()
+        tests_pkg.joinpath("__init__.py").write_text("", encoding="utf-8")
+        tests_pkg.joinpath("test_some.py").write_text(
+            "def test_something():\n    assert True", encoding="utf-8"
+        )
+
+        # Run pytest with --pyargs from the directory containing the module
+        result = pytester.runpytest("--pyargs", "amodule.tests")
+        assert result.ret == ExitCode.OK
+        result.stdout.fnmatch_lines(["*1 passed*"])
+
     def test_cmdline_python_package(self, pytester: Pytester, monkeypatch) -> None:
         import warnings