@Test
  void canOverrideSSLSocketFactory() throws IOException, InterruptedException {
    server.useHttps(TrustingSSLSocketFactory.get("localhost"), false);
    server.enqueue(new MockResponse());

    TestInterface api =
        newBuilder().target(TestInterface.class, "https://localhost:" + server.getPort());

    api.post("foo");
  }
Tests client-specific behavior, such as ensuring Content-Length is sent when specified.
core/src/test/java/feign/client/DefaultClientTest.java