TestContainers Integration testing without the hassle Sergei @bsideup Egorov

About me • Work at Uvita GmbH, Berlin • Apache Groovy committer • TestContainers’ co-maintainer • In love with Docker since 2013 @bsideup

Integration testing Why it matters?

@bsideup

@bsideup

Verify how your software product will behave in real- world conditions

Isolated from other system components to avoid false negatives

Real: databases, file systems, network interfaces, …

Grey box testing - we know some inner details, but mostly use public APIs

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Unit testing • Simulation tests are green, yay! • Everything is mocked • DB is written by others, why should I test it? @bsideup

Integration testing https://commons.wikimedia.org/wiki/File:Cd4007.jpg • Jeez, how did it passed the Unit testing? • Is it a smoke? @#$%! YES IT IS! • Who knew that 100w soldering gun was a bit too powerful for it? @bsideup

System testing https://commons.wikimedia.org/wiki/File:UART_8250_Microchip.jpg • Takes a lot of time to solder • “Oh no, the power bus is too far away from my microchip!” • Interference between the components @bsideup

Production @bsideup

Integration testing Real-world, but isolated testing Spot the issues before the real environment Can be run during the development You have to start real databases Should be cross-platform Slower than Unit testing Pros Cons @bsideup

Obvious solution

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Abstraction layer

CI friendly

Cross-platform

Docker Compose FTW! redis:
 image: redis
 ports:
 - "6379:6379"
 postgres:
 image: postgres
 ports:
 - "5432:5432"
 elasticsearch:
 image: elasticsearch:5.0.0
 ports:
 - "9200:9200"
 @bsideup

But…

Declarative YAML redis:
 image: redis
 ports:
 - "6379:6379"
 postgres:
 image: postgres
 ports:
 - "5432:5432"
 elasticsearch:
 image: elasticsearch:5.0.0
 ports:
 - "9200:9200"
 @bsideup

No ports randomization redis:
 image: redis
 ports:
 - "6379:6379"
 postgres:
 image: postgres
 ports:
 - "5432:5432"
 elasticsearch:
 image: elasticsearch:5.0.0
 ports:
 - "9200:9200"
 @bsideup

Container per test? redis:
 image: redis
 ports:
 - "6379:6379"
 postgres:
 image: postgres
 ports:
 - "5432:5432"
 elasticsearch:
 image: elasticsearch:5.0.0
 ports:
 - "9200:9200"
 @bsideup

IDE integration? @bsideup

Fighting with Docker environment

There is no place like

There is no place like Except Docker Machine

Can we improve that?

@bsideup

@bsideup Remove the database

@bsideup Remove the database

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TestContainers • http://github.com/testcontainers/testcontainers-java • Wraps docker-java library • Docker environment discovery (Win, Mac, Linux) • Will start docker-machine if it’s not started yet • Containers cleanup on JVM shutdown @bsideup

As simple as PostgreSQLContainer postgresql = new PostgreSQLContainer()
 
 GenericContainer redis = new GenericContainer("redis:3")
 .withExposedPorts(6379) @bsideup

Users

Use case #1: testing of microservices • REST service • Java, Spring Boot • Redis and PostgreSQL • Calls some other micro-services @bsideup

@RunWith(SpringRunner.class) @SpringBootTest(webEnvironment = RANDOM_PORT) @ContextConfiguration(initializers = Initializer.class) public abstract class AbstractIntegrationTest { @ClassRule public static PostgreSQLContainer postgreSql = new PostgreSQLContainer(); @ClassRule public static GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); @ClassRule public static MockServerContainer mockServer = new MockServerContainer(); } @bsideup

@RunWith(SpringRunner.class) @SpringBootTest(webEnvironment = RANDOM_PORT) @ContextConfiguration(initializers = Initializer.class) public abstract class AbstractIntegrationTest { @ClassRule public static PostgreSQLContainer postgreSql = new PostgreSQLContainer(); @ClassRule public static GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); @ClassRule public static MockServerContainer mockServer = new MockServerContainer(); } Still using all the Spring goodies! @bsideup

@RunWith(SpringRunner.class) @SpringBootTest(webEnvironment = RANDOM_PORT) @ContextConfiguration(initializers = Initializer.class) public abstract class AbstractIntegrationTest { @ClassRule public static PostgreSQLContainer postgreSql = new PostgreSQLContainer(); @ClassRule public static GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); @ClassRule public static MockServerContainer mockServer = new MockServerContainer(); } External dependencies @bsideup

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public class MockServerContainer extends GenericContainer { public MockServerContainer() { super("jamesdbloom/mockserver:latest"); addExposedPorts(8080); } private MockServerClient client; @Override protected void containerIsStarted(InspectContainerResponse containerInfo) { super.containerIsStarted(containerInfo); client = new MockServerClient(getContainerIpAddress(), getMappedPort(getExposedPorts().get(0))); } } @bsideup

public class MockServerContainer extends GenericContainer { public MockServerContainer() { super("jamesdbloom/mockserver:latest"); addExposedPorts(8080); } private MockServerClient client; @Override protected void containerIsStarted(InspectContainerResponse containerInfo) { super.containerIsStarted(containerInfo); client = new MockServerClient(getContainerIpAddress(), getMappedPort(getExposedPorts().get(0))); } } @bsideup

Demo

Use case #2: Docker as Selenium driver • Selenium/Selenide tests • No need to install Chrome/Firefox/etc • CI friendly @bsideup

@Rule public BrowserWebDriverContainer chrome = new BrowserWebDriverContainer() .withDesiredCapabilities(DesiredCapabilities.chrome()) .withRecordingMode(RECORD_ALL, new File("target")); @bsideup

@Rule public BrowserWebDriverContainer chrome = new BrowserWebDriverContainer() .withDesiredCapabilities(DesiredCapabilities.chrome()) .withRecordingMode(RECORD_ALL, new File("target")); RemoteWebDriver driver = chrome.getWebDriver(); driver.get("https://wikipedia.org"); WebElement searchInput = driver.findElementByName("search"); searchInput.sendKeys("Rick Astley"); searchInput.submit(); WebElement otherPage = driver.findElementByLinkText("Rickrolling"); otherPage.click(); boolean expectedTextFound = driver.findElementsByCssSelector("p") .stream() .anyMatch(element -> element.getText().contains("meme")); assertTrue("The word 'meme' is found on a page about rickrolling", expectedTextFound); @bsideup

@Rule public BrowserWebDriverContainer chrome = new BrowserWebDriverContainer() .withDesiredCapabilities(DesiredCapabilities.chrome()) .withRecordingMode(RECORD_ALL, new File("target")); RemoteWebDriver driver = chrome.getWebDriver(); driver.get("https://wikipedia.org"); WebElement searchInput = driver.findElementByName("search"); searchInput.sendKeys("Rick Astley"); searchInput.submit(); WebElement otherPage = driver.findElementByLinkText("Rickrolling"); otherPage.click(); boolean expectedTextFound = driver.findElementsByCssSelector("p") .stream() .anyMatch(element -> element.getText().contains("meme")); assertTrue("The word 'meme' is found on a page about rickrolling", expectedTextFound); import org.openqa.selenium.remote.RemoteWebDriver; @bsideup

@Rule public BrowserWebDriverContainer chrome = new BrowserWebDriverContainer() .withDesiredCapabilities(DesiredCapabilities.chrome()) .withRecordingMode(RECORD_ALL, new File("target")); RemoteWebDriver driver = chrome.getWebDriver(); driver.get("https://wikipedia.org"); WebElement searchInput = driver.findElementByName("search"); searchInput.sendKeys("Rick Astley"); searchInput.submit(); WebElement otherPage = driver.findElementByLinkText("Rickrolling"); otherPage.click(); boolean expectedTextFound = driver.findElementsByCssSelector("p") .stream() .anyMatch(element -> element.getText().contains("meme")); assertTrue("The word 'meme' is found on a page about rickrolling", expectedTextFound); @bsideup

Demo

• http://testcontainers.org • testcontainers/testcontainers-java-examples • Integration testing is a must • Docker works great for testing • Unified env for Dev and CI @bsideup

Questions?

@bsideup bsideup

https://commons.wikimedia.org/wiki/File:Thats_all_folks.svg