Allow user to overwrite browser_context_args using a marker

pytest_playwright/pytest_playwright.py

@@ -59,6 +59,10 @@ def pytest_configure(config: Any) -> None:
     config.addinivalue_line(
         "markers", "only_browser(name): mark test to run only on a specific browser"
     )
+    config.addinivalue_line(
+        "markers",
+        "browser_context_args(**kwargs): provide additional arguments to browser.new_context()",
+    )
 
 
 # Making test result information available in fixtures
@@ -206,6 +210,11 @@ def context(
     request: pytest.FixtureRequest,
 ) -> Generator[BrowserContext, None, None]:
     pages: List[Page] = []
+
+    context_args_marker = next(request.node.iter_markers("browser_context_args"), None)
+    additional_context_args = context_args_marker.kwargs if context_args_marker else {}
+    browser_context_args.update(additional_context_args)
+
     context = browser.new_context(**browser_context_args)
     context.on("page", lambda page: pages.append(page))
 

tests/test_playwright.py

@@ -170,6 +170,30 @@ def test_browser_context_args(page):
     result.assert_outcomes(passed=1)
 
 
+def test_user_defined_browser_context_args(testdir: pytest.Testdir) -> None:
+    testdir.makeconftest(
+        """
+        import pytest
+
+        @pytest.fixture(scope="session")
+        def browser_context_args():
+            return {"user_agent": "foobar"}
+    """
+    )
+    testdir.makepyfile(
+        """
+        import pytest
+
+        @pytest.mark.browser_context_args(user_agent="overwritten", locale="new-locale")
+        def test_browser_context_args(page):
+            assert page.evaluate("window.navigator.userAgent") == "overwritten"
+            assert page.evaluate("window.navigator.languages") == ["new-locale"]
+    """
+    )
+    result = testdir.runpytest()
+    result.assert_outcomes(passed=1)
+
+
 def test_chromium(testdir: pytest.Testdir) -> None:
     testdir.makepyfile(
         """