def METHOD_NAME(self):
    with self.app_test.test_client() as t_client:
        # On API blueprint, check we get an HTML doc page but a json 404
        response = t_client.get('/api/docs')
        assert response.status_code == 200
        assert response.mimetype == 'text/html'
        response = t_client.get('/api/not_valid')
        assert response.status_code == 404
        assert response.mimetype == 'application/json'
        # But the rest of the app gives the HTML 404
        response = t_client.get('/about', follow_redirects=True)
        assert response.status_code == 200
        assert response.mimetype == 'text/html'
        response = t_client.get('/not_about')
        assert response.status_code == 404
        assert response.mimetype == 'text/html'