Add integration test

test/integration.groovy

@@ -0,0 +1,20 @@
+package test
+
+@Grab("spring-boot-starter-test")
+
+@SpringApplicationConfiguration(classes=app.MainController)
+@WebAppConfiguration
+@IntegrationTest('server.port:0')
+@DirtiesContext
+class IntegrationTests {
+
+  @Value('${local.server.port}')
+  int port
+  
+  @Test
+  void testHome() {
+    String body = new TestRestTemplate().getForObject('http://localhost:' + port, String)
+    assertTrue('Wrong body:\n' + body, body.contains('action="/starter.zip"'))
+  }
+  
+}