@Test
  void canCreateWithExplicitCredentials() throws Exception {
    Proxied proxied =
        new Proxied(
            TrustingSSLSocketFactory.get(),
            null,
            new Proxy(Proxy.Type.HTTP, proxyAddress),
            "user",
            "password");
    assertThat(proxied).isNotNull();
    assertThat(proxied.getCredentials()).isNotBlank();

    HttpURLConnection connection =
        proxied.getConnection(URI.create("http://www.example.com").toURL());
    assertThat(connection).isNotNull().isInstanceOf(HttpURLConnection.class);
  }
Test that the proxy is being used, but don't check the credentials. Credentials can still be
used, but they must be set using the appropriate system properties and testing that is not what
we are looking to do here.
core/src/test/java/feign/client/DefaultClientTest.java