Add failIfNoTests to samples' build setup.

samples/standalone/restdocs/http-server/build.gradle

@@ -58,6 +58,14 @@ test {
 	testLogging {
 		exceptionFormat = 'full'
 	}
+	afterSuite { desc, result ->
+		if (!desc.parent) {
+			println "Results: (${result.testCount} tests, ${result.successfulTestCount} successes, ${result.failedTestCount} failures, ${result.skippedTestCount} skipped)"
+			if (result.testCount == 0) {
+				throw new IllegalStateException("No tests were found. Failing the build")
+			}
+		}
+	}
 }
 
 contracts {

samples/standalone/restdocs/http-server/pom.xml

@@ -121,6 +121,12 @@
 					</execution>
 				</executions>
 			</plugin>
+			<plugin>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<configuration>
+					<failIfNoTests>true</failIfNoTests>
+				</configuration>
+			</plugin>
 			<!-- tag::plugin[] -->
 			<plugin>
 				<groupId>org.springframework.cloud</groupId>