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
From Unit to Deployment Tests
Alex Soto
@alexsotob

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

3. @alexsotob3
Questions

4. @alexsotob4
Click to add subtitle
ASSERTIONS

5. @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());
}
5
Readable name
BDD style
AssertEquals Order
Depends On Equals

6. @alexsotob6
AssertJ

7. @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);
}
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Static Import
Readable Assertions
Not Depending on
Equals

8. @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”);
}
8
Train Call (IDE
support) Create List with
getName Result
Methods for String

9. @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));
});
}
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Java 8 Lambda
All assertions in Block

10. @alexsotob10
Things go
Wrong

11. @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());
}
}
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Fails if Success

12. @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");
}
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Special Attribute

13. @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”);
}
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Catch Exception of Lambda
Assertion Methods for
Exceptions

14. @alexsotob
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
Benefits of AssertJ
14

15. @alexsotob15
Don’t Sleep, Just Wait

16. @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);
}
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Asynchronous Call
Slowest Machine Time

17. @alexsotob17

18. @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);
}
18
Asynchronous Call
Polls until True or Timeout

19. @alexsotob
Deadlock Detection
Different Pollings
Fixed, Fibonacci, Iterative, Custom
Simple Library
No dependencies, No magic
Benefits of Awaitility
19

20. @alexsotob20
REST API

21. @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"]
}
]
}
21
Simple Objects
Array of Objects

22. @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"");
}
22
Prepare Connection
Do connection
Get content
Manipulate String

23. @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"");
23

24. @alexsotob24

25. @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"));
}
25
GET Http Method with
Placeholders
GPath Expression

26. @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())...
26
Use domain directly
Use Spec Builder
Reuse Everywhere

27. @alexsotob
REST-assured Auth
given().auth().oauth2(accessToken).when()...
given().auth().form("John", "Doe", springSecurity().withCsrfFieldName("_csrf")).when()...
given().auth().basic("username", "password").when()...
27

28. @alexsotob
Custom Parsers
Not just JSON and XML
SSL Support
.relaxedHTTPSValidation()
Filters
Input/Output modification
JSON Schema Validation
Content not Important
More Features
of Rest-Assured
28

29. @alexsotob29
(Micro) Services Dependencies

30. @alexsotob
Network Down
Service Down
Limits on API
Component Not in Control
Micro-Services Dependencies Hell
Problems with Services
30

31. @alexsotob
Mock Http Component
Stub/Fake Http Server
Service Virtualization
Possible Solutions
31

32. @alexsotob32
Service Virtualization

33. @alexsotob
Service Virtualization Capture Mode
33
Service A External Network Service B
Scripts
Proxy

34. @alexsotob
Service Virtualization Simulate Mode
34
Service A External Network Service B
Scripts
Proxy

35. @alexsotob35

36. @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");
}
36
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

37. @alexsotob37
Persistence Tests

38. @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);
}
38
Prepare Database
Execute Query

39. @alexsotob39
APE

40. @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();
}
40
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

41. @alexsotob
APE SQL example
@After
public void clean_database() {
// Given:
rdbmsPopulator.forUri(jdbcUri).withDriver(Driver.class).withUsername("sa")
.withPassword("").usingDataSet("composers.yml")
.clean();
}
41
Clean After Test
Clean Database

42. @alexsotob
Boilerplate Code
Programmatic/Declarative
@UsingDataSet/@ShouldMatchDataSet
SQL Support
DBUnit and Flyway
REST API Support
Postman Collections
NoSQL Support
MongoDB, Couchbase, CouchDB, Vault, Redis, Infinispan
Benefits of Arquillian APE
42

43. @alexsotob43
Containers Are Burning

44. @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
44
Docker Run
Docker Compose Run
Run tests
Stop Docker Containers

45. @alexsotob45
CUBE

46. @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"));
}
}
46
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

47. @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() {
}
47
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

48. @alexsotob
Arquillian Cube K8S
@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();
}
}
48
Kubernetes Client
URL to Access Service
AssertJ Custom Assertions

49. @alexsotob49
Let’s Wind Down

50. @alexsotob
From Low to High Level
Unit, Component, Integration, Deployment
Not Just for Micro-Services
Same can be reused for monolithic
Improves Readability
Tests are meant to be read
Conclusions
50

51. @alexsotob51
Keep Calm
And Write Tests