def test_blocklist_nonfatal(self):
        """test 'pip install <blocklisted-nonfatal-package>'."""
        output = self.run_command("pip --verbose install matplotlib", exitcode=0)
        self.assertIn("Warning: package 'matplotlib' is blocklisted, but marked as non-fatal.", output)
        self.assertIn("This package is already bundled with Pythonista", output)
        self.assertNotIn("PackageBlocklisted", output)
        self.assertNotIn("Package installed: matplotlib", output)
test 'pip install <blocklisted-nonfatal-package>'.
tests/pip/test_pip.py