PYTEST_ADDOPTS=--cov pytest test_foo.py

[blueyed]

pytest-cov has an argument with nargs='?': https://github.com/pytest-dev/pytest-cov/blob/7205428bfb9ab9f8dbcaeefe23ce5fe426bb06b9/src/pytest_cov/plugin.py#L55-L58

I've just noticed that with PYTEST_ADDOPTS=--cov pytest foo "foo" becomes the arg for it, which really confused me.

It looks like the PYTEST_ADDOPTS handling injects the value, but it should get handled separately/isolated.

[blueyed]

A failing test for this:

diff --git a/testing/test_config.py b/testing/test_config.py
index b7c68ea4..1b444ab6 100644
--- a/testing/test_config.py
+++ b/testing/test_config.py
@@ -1109,6 +1109,28 @@ def test_addopts_from_ini_not_concatenated(self, testdir):
         )
         assert result.ret == _pytest.main.EXIT_USAGEERROR
 
+    @pytest.mark.xfail
+    def test_addopts_from_ini_with_default(self, testdir):
+        """addopts from ini should not take values from normal args (#4265)."""
+        testdir.makeconftest(
+            """
+            def pytest_addoption(parser):
+                group = parser.getgroup('cov')
+                group.addoption('--cov', action='append', default=[],
+                                dest="cov_source", nargs='?', const=True)
+            """)
+        testdir.makeini(
+            """
+            [pytest]
+            addopts=--cov
+        """)
+        testdir.makepyfile(test_test="""
+            def test_test(request):
+                assert request.config.getoption("cov_source") == [True]
+        """)
+        result = testdir.runpytest("test_test.py")
+        assert result.ret == _pytest.main.EXIT_OK
+
     def test_override_ini_does_not_contain_paths(self):
         """Check that -o no longer swallows all options after it (#3103)"""
         from _pytest.config import get_config