如何（单元）测试方法向 MS Teams 频道发送 http 请求？

Question

I've written a monitoring service class performing a database check for entries of a certain (considered erroneous) state. Based on the result of the database query, the service will send a notification to a Microsoft Teams channel using its Connector/Webhook functionality. It works all fine so far, but I can't wrap my head around how to properly test the respective methods. It's mainly the method sending the notification to Teams I'm struggling with:

public HttpStatus sendNotificationToTeams(MsTeamsCard card) throws JsonProcessingException {
        HttpHeaders headers = new HttpHeaders();
        ObjectWriter writer = new ObjectMapper().writer();
        Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(WebConfig.PROXY_HOST, WebConfig.PROXY_PORT));
        SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();

        // Setup RestTemplate. Proxy is required, otherwise request returns HTTP 500 with misleading error message (array index out of bounds)
        requestFactory.setProxy(proxy);
        RestTemplate restTemplate = new RestTemplate(requestFactory);

        // HTTP request incl. setup
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<String> request = new HttpEntity<>(writer.writeValueAsString(card), headers);
        ResponseEntity<String> response = restTemplate.exchange(this.webhookUrl, HttpMethod.POST, request, String.class);
        return response.getStatusCode();
    }

I think I should definitely test this method since it's not trivial at all. However, there's not much that I think could reasonalby fail inside this method that is related to its particular arrangement of code - of course there may be problems, but things like network issues are out of scope of (unit) tests for this method. So how would I test this method reliably? I'm asking more from a general testing point of view (which is where I really lack knowledge) than requesting concrete help with a test framework or something (JUnit 4 is used btw). For example, one point is that I can't check the results of the HTTP call even if I mock it, because it requires a specific answer from Teams: the request might be successful but something could be wrong with Teams, and I can't really mock that. But maybe I'm just thinking too complicated here.

Answer 1

If you are looking for unit-testing your http-connector, you can do it with Wiremock. Check out this tutorial

For instance

@Test
public void shouldSendNotification() {
  String path = "/endpoint";
  wiremock.stubFor(get(urlEqualTo(path))
          .willReturn(aResponse()
                  .withStatus(200))
  );
  HttpStatus status = sendNotificationToTeams(...);
  assertThat(status).isEqualTo(200);
}