docs: add unit test

docs/faq.md

@@ -20,6 +20,40 @@ Either create a custom spring controller to serve the file or [serve static reso
 
 Note: `springwolf-ui` doesn't support the full AsyncAPI spec.
 
+### Unit test verification
+
+With the AsyncApi artifact (i.e. at `src/test/resources/asyncapi.json) checked into the repository,
+a unit test can verify that the current code still matches the expected AsyncApi specification.
+Additionally, a diff reveals (un)expected changes.
+
+Example unit test:
+```java
+@SpringBootTest(
+     classes = {SpringwolfKafkaExampleApplication.class},
+     webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class ApiIntegrationTest {
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Test
+    void asyncApiResourceArtifactTest() throws IOException {
+        String url = "/springwolf/docs";
+        String actual = restTemplate.getForObject(url, String.class);
+
+        // writing the actual file can be useful for debugging (remember: gitignore)
+        Files.writeString(Path.of("src", "test", "resources", "asyncapi.actual.json"), actual);
+
+        InputStream s = this.getClass().getResourceAsStream("/asyncapi.json");
+        String expected = new String(s.readAllBytes(), StandardCharsets.UTF_8).trim();
+
+        assertEquals(expected, actual);
+    }
+}
+```
+
+For a full example, check the [springwolf-kafka-example ApiIntegrationTest](https://github.com/springwolf/springwolf-core/blob/master/springwolf-examples/springwolf-kafka-example/src/test/java/io/github/springwolf/examples/kafka/ApiIntegrationTest.java)
+
 ## Troubleshooting
 
 ### Show `debug` output in the logs

src/components/HomepageFeatures.js

@@ -8,7 +8,7 @@ const FeatureList = [
     title: 'Effortless API documentation',
     description: (
       <>
-        Springwolf uses metadata already provided in the code 
+        Springwolf uses metadata already provided in the code
         to automatically create documentation.
       </>
     ),
@@ -26,15 +26,17 @@ const FeatureList = [
     title: 'Powered by AsyncAPI v3',
     description: (
       <>
-        The generated documentation is compliant with the <Link to='https://www.asyncapi.com/'>AsyncAPI specification</Link>.
+        The generated documentation is compliant with the
+        <Link to='https://www.asyncapi.com/'>AsyncAPI specification</Link>.
       </>
     ),
   },
   {
     title: 'Optional web-ui',
     description: (
       <>
-        Single dependency ui for API testing including event publishing.
+        Single dependency for API testing including event publishing
+        (<Link to={'https://demo.springwolf.dev'}>demo</Link>).
       </>
     ),
   },
@@ -50,7 +52,24 @@ const FeatureList = [
     title: 'Integrate',
     description: (
       <>
-        Generate documentation in your CI/CD pipeline and publish to tools like <Link to="https://backstage.io">Backstage</Link>.
+        Generate documentation in your CI/CD pipeline and publish to tools like
+        <Link to="https://backstage.io">Backstage</Link>.
+      </>
+    ),
+  },
+  {
+    title: 'Verify',
+    description: (
+      <>
+        Use an unit test to check for (un)expected changes.
+      </>
+    ),
+  },
+  {
+    title: 'Participate',
+    description: (
+      <>
+        Something missing? Features requests and contributions are welcome.
       </>
     ),
   },