Relaxed SSL Validation for Rest Template

WireMock allows you to stub a "secure" server with an "https" URL protocol. If your application wants to contact that stub server in an integration test, then it will find that the SSL certificates are not valid (it’s the usual problem with self-installed certificates). The best option is often to just re-configure the client to use "http", but if that’s not open to you then you can ask Spring to configure an HTTP client that ignores SSL validation errors (just for tests).

To make this work with minimum fuss you need to be using the Spring Boot RestTemplateBuilder in your app, e.g.

@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
    return builder.build();
}

This is because the builder is passed through callbacks to initalize it, so the SSL validation can be set up in the client at that point. This will happen automatically in your test if you are using the @AutoConfigureWireMock annotation (or the stub runner). If you are using the JUnit @Rule approach you need to add the @AutoConfigureHttpClient annotation as well:

@RunWith(SpringRunner.class)
@SpringBootTest("app.baseUrl=https://localhost:6443")
@AutoConfigureHttpClient
public class WiremockHttpsServerApplicationTests {

    @ClassRule
    public static WireMockClassRule wiremock = new WireMockClassRule(
            WireMockSpring.options().httpsPort(6443));
...
}

If you are using spring-boot-starter-test then you will have the Apache HTTP client on the classpath and it will be selected by the RestTemplateBuilder and configured to ignore SSL errors. If you are using the default java.net client you don’t need the annotation (but it won’t do any harm). There is no support currently for other clients, but it may be added in future releases.