    def test_plaintext_encoding(self):
        """Response content type is text/plain when Accept header is missing in request"""
        app = make_asgi_app(self.registry)
        self.seed_app(app)
        self.send_input({"type": "http.request", "body": b""})

        content_type = self.get_response_header_value('Content-Type').split(";")[0]
        assert content_type == "text/plain"
Response content type is text/plain when Accept header is missing in request
tests/test_asgi.py