One of the most important benefits of automated testing is to ensure a fast and safe code refactoring to evolve our system architecture. The main problem is how to write tests that are easy to write, easy to follow and not time consuming during development nor execution time. In this session, we are going to explore some powerful Java testing libraries that will help you write better (unit) tests focusing on the main Unicorns architecture challenges such as validating microservices endpoints, remote calls to other microservices or just asynchronous/reactive code.

1. Testing For Unicorns
Java test apps any developer should know
Alex Soto
Red Hat Engineer
@alexsotob

2. @alexsotob2
Alex Soto
Red Hat Engineer
www.lordofthejars.com
@alexsotob
Who Am I?

3. @alexsotob3
https://www.manning.com/books/testing-java-microservices

4. @alexsotob4
Questions

5. @alexsotob5
ASSERTIONS

6. @alexsotob
JUnit Test
@Test
public void should_find_composer_by_name() {
// Given:
Composers composers = new Composers();
// When:
final Composer mozart = composers.findComposerByName("Wolfgang Amadeus Mozart");
// Then:
assertEquals("Wolfgang Amadeus Mozart", mozart.getName());
assertEquals(Era.CLASSICAL, mozart.getEra());
assertEquals(LocalDate.of(1756, 1, 27), mozart.getBirthdate());
assertEquals(LocalDate.of(1791, 12, 5), mozart.getDied());
}
6
Readable name
BDD style
AssertEquals Order
Depends On Equals

7. @alexsotob7
AssertJ

8. @alexsotob
AssertJ Test
import static org.assertj.core.api.Assertions.assertThat;
@Test
public void should_find_composer_by_name() {
// Given:
Composers composers = new Composers();
// When:
final Composer mozart = composers.findComposerByName("Wolfgang Amadeus Mozart”);
// Then:
assertThat(mozart.getName()).isEqualTo("Wolfgang Amadeus Mozart”);
assertThat(mozart).returns("Wolfgang Amadeus Mozart", Composer::getName);
assertThat(mozart.getBirthdate()).isEqualTo(LocalDate.of(1756, 1, 27));
assertThat(mozart).isEqualToComparingFieldByField(expectedMozart);
assertThat(mozart).isEqualToIgnoringNullFields(expectedMozart);
}
8
Static Import
Readable Assertions
Not Depending on
Equals

9. @alexsotob
AssertJ Test Collections
@Test
public void should_find_operas_by_composer_name() {
// Given:
Composers composers = new Composers();
// When:
final List<Opera> operas = composers.findOperasByComposerName("Wolfgang Amadeus Mozart");
// Then:
assertThat(operas)
.hasSize(2)
.extracting(Opera::getName)
.containsExactlyInAnyOrder("Die Zauberflöte", "Don Giovanni”);
}
9
Train Call (IDE
support) Create List with
getName Result
Methods for String

10. @alexsotob
AssertJ Soft Assertions
@Test
public void should_find_composer_by_name_soft_assertions() {
// Given:
Composers composers = new Composers();
// When:
final Composer mozart = composers.findComposerByName("Wolfgang Amadeus Mozart");
// Then:
SoftAssertions.assertSoftly(softly -> {
softly.assertThat(mozart.getName()).isEqualTo("Wolfgang Amadeus Mozart");
softly.assertThat(mozart.getEra()).isEqualTo(Era.CLASSICAL);
softly.assertThat(mozart.getBirthdate()).isEqualTo(LocalDate.of(1756, 1, 27));
softly.assertThat(mozart.getDied()).isEqualTo(LocalDate.of(1791, 12, 5));
});
}
10
Java 8 Lambda
All assertions in Block

11. @alexsotob11
Things go
Wrong

12. @alexsotob
Try/Catch
@Test
public void should_throw_exception_if_composer_not_found() {
// Given:
Composers composers = new Composers();
// When:
try {
final Composer salieri = composers.findComposerByName("Antonio Salieri");
fail();
} catch (IllegalArgumentException e) {
// Then:
assertEquals("Composer Antonio Salieri is not found", e.getMessage());
}
}
12
Fails if Success

13. @alexsotob
JUnit
@Test(expected = IllegalArgumentException.class)
public void should_throw_exception_if_composer_not_found_version_2() {
// Given:
Composers composers = new Composers();
// When:
final Composer salieri = composers.findComposerByName("Antonio Salieri");
}
13
Special Attribute

14. @alexsotob
AssertJ Exceptions
@Test
public void should_throw_exception_if_composer_not_found_version_3() {
// Given:
Composers composers = new Composers();
// When:
Throwable thrown = catchThrowable(() -> composers.findComposerByName("Antonio Salieri"));
// Then:
assertThat(thrown).isInstanceOf(IllegalArgumentException.class)
.withFailMessage("Composer Antonio Salieri is not found”);
}
14
Catch Exception of Lambda
Assertion Methods for
Exceptions

15. @alexsotob15
DEMO

16. @alexsotob16
Benefits of AssertJ
> IDE Friendly
Ctrl + Space works
> Assertions Generation
ComposerAssert.assertThat(mozart).hasName(“Mozart”).hasBirthdate(LocalDate.of(..);
> Out-of-the-Box Assertions
Guava, Joda, DB, Neo4j and Swing

17. @alexsotob17
Don’t Sleep, Just Wait

18. @alexsotob
Asynchronous Call
@Test
public void should_play_operas() throws InterruptedException {
// Given:
final Opera nozzeDiFigaro = ...;
Gramophone gramophone = new Gramophone();
// When:
gramophone.play(nozzeDiFigaro);
// Then:
TimeUnit.SECONDS.sleep(3);
assertThat(gramophone.getCurrentOpera()).isEqualTo(nozzeDiFigaro);
}
18
Asynchronous Call
Slowest Machine Time

19. @alexsotob19

20. @alexsotob
Awaitility Example
@Test
public void should_play_operas_version_2() {
// Given:
final Opera nozzeDiFigaro = Composers.OperaFactory
.createOpera("Le Nozze di Figaro")
.language(Language.ITALIAN).librettist("Lorenzo Da Ponte")
.roles("Count Almaviva", "Countess Rosina", "Susanna", "Figaro")
.build();
Gramophone gramophone = new Gramophone();
// When:
gramophone.play(nozzeDiFigaro);
// Then:
await().atMost(5, TimeUnit.SECONDS).until(gramophone::isPlaying);
assertThat(gramophone.getCurrentOpera()).isEqualTo(nozzeDiFigaro);
}
20
Asynchronous Call
Polls until True or Timeout

21. @alexsotob21
DEMO

22. @alexsotob22
Benefits of Awaitility
> Deadlock Detection
> Different Pollings
Fixed, Fibonacci, Iterative, Custom
> Simple Library
No dependencies, No magic

23. @alexsotob23
REST API

24. @alexsotob
GET /Ludwig+van+Beethoven
{
"name": "Ludwig van Beethoven",
"era": "ROMANTIC",
"birthdate": {},
"died": {},
"operas": [
{
"name": "Fidelio",
"librettist": "Georg Friedrich Treitschke",
"language": "GERMAN",
"roles": ["Rocco", "Leonore", "Florestan"]
}
]
}
24
Simple Objects
Array of Objects

25. @alexsotob
HttpClient Example
@Test
public void should_find_composer() throws IOException, URISyntaxException {
// Given:
URIBuilder uriBuilder = new URIBuilder("http://localhost:8080/");
uriBuilder.setPath("Ludwig van Beethoven");
// When:
final Content bodyContent = Request.Get(uriBuilder.build())
.execute().returnContent();
String body = bodyContent.asString();
// Then:
assertThat(body).contains(""name":"Ludwig van Beethoven"")
.contains(""librettist":"Georg Friedrich Treitschke"");
}
25
Prepare Connection
Do connection
Get content
Manipulate String

26. @alexsotob
WebDriver Example
// Given:
WebDriver browser = new FirefoxDriver();
URIBuilder uriBuilder = new URIBuilder("http://localhost:8080/");
uriBuilder.setPath("Ludwig van Beethoven");
// When:
browser.navigate().to(uriBuilder.build());
// Then:
assertThat(browser.getPageSource()).contains(""name":"Ludwig van Beethoven"");
26

27. @alexsotob27

28. @alexsotob
REST-assured Example
@Test
public void should_find_composer() {
given()
.when()
.get("{composer}", "Ludwig van Beethoven")
.then()
.assertThat()
.body("name", is("Ludwig van Beethoven"))
.body("operas.size()", is(1))
.body("operas.name", hasItems("Fidelio"));
}
28
GET Http Method with
Placeholders
GPath Expression

29. @alexsotob
REST-assured Example
@Test
public void should_insert_composer() {
Composer composer = ....;
given()
.param("parameter1", "parameterValue")
.body(composer)
.when()
.post()
.then()
.assertThat()
.statusCode(201);
}
29
Create POJO object
Set Params
Set POJO as Body
POST Http Method
Assertion on Status Code

30. @alexsotob
REST-assured Request Logging
given().log().all(). .. // Log all request specification details
given().log().params(). .. // Log only the parameters of the request
given().log().body(). .. // Log only the request body
given().log().headers(). .. // Log only the request headers
given().log().cookies(). .. // Log only the request cookies
given().log().method(). .. // Log only the request method
given().log().path(). .. // Log only the request path
30

31. @alexsotob
REST-assured Response Logging
get("/x").then().log().ifError()
get("/x").then().log().all()
given().log().ifValidationFails()
get("/x").then().log().ifStatusCodeIsEqualTo(302)
given().config(RestAssured.config()
.logConfig(logConfig().enableLoggingOfRequestAndResponseIfValidationFails())
)
31

32. @alexsotob
REST-assured Request Specification
.get("http://example.com/{composer}", "Ludwig van Beethoven")
RequestSpecBuilder builder = new RequestSpecBuilder();
builder.setBaseUri("http://example.com");
given().spec(builder.build())...
32
Use domain directly
Use Spec Builder
Reuse Everywhere

33. @alexsotob
REST-assured Auth
given().auth().oauth2(accessToken).when()...
given().auth().form("John", "Doe", springSecurity().withCsrfFieldName("_csrf")).when()...
given().auth().basic("username", "password").when()...
33

34. @alexsotob34
More Features of Rest-Assured
> Custom Parsers
Not just JSON and XML
> SSL Support
.relaxedHTTPSValidation()
> Filters
Input/Output modification
> JSON Schema Validation
Content not Important

35. @alexsotob35
Service Virtualization

36. @alexsotob
Service Virtualization Capture Mode
36
Service A External Network Service B
Scripts
Proxy

37. @alexsotob
Service Virtualization Simulate Mode
37
Service A External Network Service B
Scripts
Proxy

38. @alexsotob38

39. @alexsotob
Hoverfly Example
@ClassRule
public static HoverflyRule hoverflyRule =
HoverflyRule.inCaptureOrSimulationMode("getcomposers.json");
@Test
public void should_get_composers_from_composers_microservice() {
// Given:
ComposersGateway composersGateway = new ComposersGateway("operas.com", 8081);
// When:
Composer composer = composersGateway.getComposer("Ludwig van Beethoven");
// Then:
assertThat(composer.getName()).isEqualTo("Ludwig van Beethoven");
}
39
Start Hoverfly
Use Real Host
Get Data from Real
{
"data" : {
"pairs" : [{
"request" : {
"path" : "/Ludwig van Beethoven",
"method" : "GET",
"destination" : “operas.com:8081",
...
}
"response" : {
"status" : 200,
"body" : "{"name":"Ludwig van Beethoven",}",
"encodedBody" : false,
"headers" : {
"Connection" : [ "keep-alive" ],
...
}
}
}
}
Get Data from Proxy

40. @alexsotob
Hoverfly Example Simulate
private static String RESPONSE = "[n"
+ " {n"
+ " "name": "Moon",n"
+ " "villain": "Gru",n"
+ " "wiki": "https://en.wikipedia.org/wiki/Moon"n"
+ " }
+ "]";
@ClassRule
public static HoverflyRule hoverflyRule =
HoverflyRule.inSimulationMode(dsl(
service("crimesdb:8080")
.get("/crimes/Gru")
.willReturn(success(RESPONSE, "application/json"))
40
Hardcoded response
Starts in simulate
Host
Program interactions

41. @alexsotob41
Benefits of Service Virtualization and Hoverfly
> Do not relay on network
Yet testing all stack trace
> Hoverfly multilanguage
Can be used as standalone proxy
> Hoverfly JVM
Integration with JVM proxy settings

42. @alexsotob42
Contract Tests

43. @alexsotob43
Consumer
request
response Stub Server
expectations
Provider
request
response
Result
Define Consumer Expectations Verify Expectations On Provider

44. @alexsotob44
@RunWith(Arquillian.class)
public class CrimesConsumerContractTest {
@StubServer URL pactServer;
@Pact(provider = "crimes", consumer = "villains")
public RequestResponsePact returnListOfCrimes(PactDslWithProvider builder) {
return builder
.uponReceiving("Gru villain to get all Crimes")
.path("/crimes/Gru")
.method("GET")
.willRespondWith()
.status(200)
.body(RESPONSE)
.toPact();
}
@Test
@PactVerification("crimes")
public void should_get_list_of_crimes_by_villain() {
CrimesGateway crimesGateway = new CrimesGateway(webClient, pactServer);
final Single<JsonArray> gruCrimes = crimesGateway.getCrimesByVillainName("Gru");
}
Stub/proxy Server URL
Defines service interaction
Provides predefined Req/Res
Executes real requests
Consumer side

45. @alexsotob45
@RunWith(Arquillian.class)
@Provider("crimes")
@ContractsFolder("~/crimescontract")
public class CrimesContractTest {
@ArquillianResource
Target target;
@Test
public void should_validate_contract() {
assertThat(target).withUrl(getCrimesServer()).satisfiesContract();
}
}
Provider under validation
Location of contracts
Http Client
Asserts All Interactions are correct
Provider side

46. @alexsotob46
DEMO

47. @alexsotob47
Benefits of CDC and Pact
> Pact Foundation
Pact specification v3
> Integration with several languages
JVM, Ruby, Python, Go, .Net, Swift, JS
> Pact Broker
Sharing contracts, API documentation, Overview of services
> Arquillian Algeron
Arquillian ecosystem + Pact, Publishers/Retrievers, JBoss Forge
> Consumer Driven Contracts
Fail fast
Independent deployments
Improve communication

48. @alexsotob48
Containers Are Burning

49. @alexsotob
Testing Containers
docker build -t myorg/myservice:1.0.0 .
docker run --rm -ti -p 8080:8080 myorg/myservice:1.0.0
docker-compose up
mvn clean test
docker-compose stop
49
Docker Run
Docker Compose Run
Run tests
Stop Docker Containers

50. @alexsotob50

51. @alexsotob
Arquillian Cube Example
@RunWith(Arquillian.class)
public class HelloWorldTest {
@ArquillianResource
@DockerUrl(containerName = "helloworld", exposedPort = 8080)
RequestSpecBuilder requestSpecBuilder;
@Test
public void should_receive_ok_message() {
RestAssured
.given()
.spec(requestSpecBuilder.build())
.when()
.get()
.then()
.assertThat().body("status", equalTo("OK"));
}
}
51
Arquillian Runner
REST-Assured Integration
Environment Resolver
Normal REST-Assured Call
helloworld:
image: jonmorehouse/ping-pong
ports:
- "8080:8080"
src/test/docker/docker-compose.yml

52. @alexsotob
Arquillian Cube DSL
@RunWith(SpringRunner.class)
@SpringBootTest(classes = PingPongController.class, webEnvironment = RANDOM_PORT)
@ContextConfiguration(initializers = PingPongSpringBootTest.Initializer.class)
public class PingPongSpringBootTest {
@ClassRule
public static ContainerDslRule redis = new ContainerDslRule("redis:3.2.6")
.withPortBinding(6379);
@Autowired
TestRestTemplate restTemplate;
@Test
public void should_get_data_from_redis() {
}
52
Spring Boot Test
Custom Initializer
Container Definition
public static class Initializer implements
ApplicationContextInitializer<ConfigurableApplicationContext> {
@Override
public void initialize(ConfigurableApplicationContext configurableApplicationContext) {
EnvironmentTestUtils.addEnvironment("testcontainers",
configurableApplicationContext.getEnvironment(),
"spring.redis.host=" + redis.getIpAddress(),
"spring.redis.port=" + redis.getBindPort(6379)
);
Sets Container Environment

53. @alexsotob53
DEMO

54. @alexsotob
Arquillian Kube
@RunWith(Arquillian.class)
public class HelloWorldTest {
@ArquillianResource
KubernetesClient client;
@Named(“hello-world-service")
@PortForward
@ArquillianResource
URL url;
@Test
public void testRunningPodStaysUp() throws Exception {
assertThat(client).deployments().pods().isPodReadyForPeriod();
}
}
54
Kubernetes Client
URL to Access Service
AssertJ Custom Assertions

55. @alexsotob55
Persistence Tests

56. @alexsotob
First attempt
@Test
public void should_find_composer_by_name() {
// Given:
clearDatabase(jdbcUri);
insertComposersData(jdbcUri);
ComposersRepository composersRepository = new ComposersRepository();
// When:
Composer mozart = composersRepository.findComposerByName("Wolfgang Amadeus Mozart");
// Then:
assertThat(mozart).returns("Wolfgang Amadeus Mozart", Composer::getName);
}
56
Prepare Database
Execute Query

57. @alexsotob57
APE

58. @alexsotob
APE SQL example
@Rule
public ArquillianPersistenceRule arquillianPersistenceRule =
new ArquillianPersistenceRule();
@DbUnit
@ArquillianResource
RdbmsPopulator rdbmsPopulator;
@Before
public void populateData() {
// Given:
rdbmsPopulator.forUri(jdbcUri).withDriver(Driver.class).withUsername("sa")
.withPassword("").usingDataSet("composers.yml")
.execute();
}
58
APE JUnit Rule
(not necessary with
Arquillian Runner)
Set DBUnit usage
Configure Connection and Dataset
Populate
composers:
- id: 1
name: Wolfgang Amadeus Mozart
birthdate: 27/1/1756
died: 5/12/1791

59. @alexsotob
APE SQL example
@After
public void clean_database() {
// Given:
rdbmsPopulator.forUri(jdbcUri).withDriver(Driver.class).withUsername("sa")
.withPassword("").usingDataSet("composers.yml")
.clean();
}
59
Clean After Test
Clean Database

60. @alexsotob60
DEMO

61. @alexsotob61
Benefits of Arquillian APE
> Boilerplate Code
> Programmatic/Declarative
@UsingDataSet/@ShouldMatchDataSet
> SQL Support
DBUnit and Flyway
> RESTAPI Support
Postman Collections
> NoSQL Support
MongoDB, Couchbase, CouchDB, Vault, Redis, Infinispan

62. @alexsotob62
Speeding Test Execution

63. @alexsotob63
Production Sources Tests
https://martinfowler.com/articles/rise-test-impact-analysis.html

64. @alexsotob
Smart Testing Maven Extension
curl -sSL https://git.io/v5jy6 | bash
64
Installs extension
mvn clean test -Dsmart.testing="new, changed, affected"
Runs only new, changed and prod related tests
mvn clean test -Dsmart.testing.mode=ordering -Dsmart.testing="new, changed, affected”
Prioritize new, changed and prod related tests

65. @alexsotob65
DEMO

66. @alexsotob66
More about Smart Testing
> Heuristics
new, changed, affected, failed and categorized
> Range of Commits
Define where you want to look at
> Configuration
System Properties or YAML file (global or per module)
> Jenkins Pipeline Shared Library
Integrate with your CI/CD pipeline
> Detection of none class changes
@WatchFile("src/main/resources/META-INF/
> Surefire based
Works with any kind of test that can be run in Surefire

67. @alexsotob67
Regression-free versions

68. @alexsotob68
Diferencia

69. @alexsotob69
Simple Comparison

70. @alexsotob70
Noise Detection Comparison

71. @alexsotob71
DEMO

72. @alexsotob72
More about Diferencia
> Comparison
with, without noise detection, strict, subset
> Formats supported
JSON, Plain Text (automatic detection), HTTPS
> Monitoring
HTTP Status, Prometheus
> Rest API
Configure, Stats
> Docker Image
Ready to use in Kubernetes and OpenShift

73. https://developers.redhat.com/
@alexsotob
asotobue@redhat.com