Get the Most out of Testing with Spring 4.2

SPRINGONE2GX
WASHINGTON, DC
© 2013-2015 Sam Brannen & Nicolas Fränkel and licensed under a Creative Commons Attribution -NonCommercial license: http://creativecommons.org/licenses/by -nc/3.0/
Get the Most out of Testing
with Spring 4.2
Sam Brannen
@sam_brannen
Nicolas Fränkel
@nicolas_frankel

© 2013-2015 Sam Brannen & Nicolas Fränkel and licensed under a Creative Commons
Attribution-NonCommercial license: http://creativecommons.org/licenses/by -nc/3.0/
Sam Brannen
• Spring and Enterprise Java Consultant @ Swiftmind
• Java Developer for over 17 years
• Spring Framework Core Committer since 2007
• Component lead for spring-test
• Creator of @AliasFor
• Spring Trainer
• Speaker on Spring, Java, and testing
• Swiss Spring User Group Lead
2

Attribution-NonCommercial license: http://creativecommons.org/licenses/by -nc/3.0/ 3
Your experts for Spring and Enterprise Java
Areas of expertise
• Spring *
• Java EE
• Software Architecture
• Software Engineering Best
Practices
Where you find us
• Zurich, Switzerland
• @swiftmind
• http://www.swiftmind.com

Nicolas Fränkel
• Developer & Architect
• Consultant
• Teacher & Trainer
• Blogger
• Book Author
4

Learning Vaadin 7
Integration Testing from the
Trenches
5
Nicolas’ Books

Agenda
• Spring Events App
• New in Spring 4.2
• JUnit vs. TestNG
• Spring Boot Tests
• Spring Security Tests
• Tips & Tricks
6

Show of hands…
7

Spring Events App
8

The Spring Events Example Application
• Spring Boot powered web app
• Simple POJO domain model: Event
• Transactional service layer
• Spring Data JPA repository layer
• Spring @MVC +Thymeleaf & REST presentation layer
• Spring Security
• https://github.com/sbrannen/spring-events
9

New in Spring Framework 4.2
10

@AliasFor
• New in Spring Framework 4.2, refined in 4.2.1 
• Used to declare aliases between attributes within an annotation
• e.g., locations and value in @ContextConfiguration, or
path and value in @RequestMapping
• Used in composed annotations to declare explicit overrides of attributes in
meta-annotations
• e.g., @Get, @Post, @GetJson, @TransactionalService
• See Spring Composed project for examples
• https://github.com/sbrannen/spring-composed
11

Composable Annotations w/ Overrides: pre 4.2
• Composable annotations can override attributes of meta-annotations
• Purely convention-based
• Matched by attribute name and type
• Can lead to potential naming conflicts
• Cannot override the value attribute
12

Convention-based Attribute Override
@Target(TYPE)
@Retention(RUNTIME)
@ContextConfiguration
@Transactional
public @interface TransactionalTest {
String[] locations() default {};
}
@TransactionalTest(locations = "/order-test-config.xml")
public class OrderRepositoryTests { }
13
seen as locations in
redeclares locations attribute
declares locations attribute

Conflict w/ Convention-based Attribute
Override
@Target(TYPE)
@Retention(RUNTIME)
@TestPropertySource
@Transactional
String[] locations() default {};
}
@TransactionalTest(locations = "/order-test-config.xml")
public class OrderRepositoryTests { }
14
both declare locations attribute
ambiguous
which one?!

Composable Annotations w/ Overrides: post
4.2
• Composable annotations can explicitly override attributes of meta-annotations,
even transitively
• Attributes within an annotation that effectively override the same attribute are
treated as implicit aliases for each other
• Explicitly declared via @AliasFor
• Can avoid potential naming conflicts
• Can even override the value attribute
15

Avoid Attribute Override Conflict w/ @AliasFor
(1)
@TestPropertySource
@Transactional
@AliasFor(annotation = ContextConfiguration.class,
attribute = "locations")
String[] xmlFiles() default {};
@AliasFor(annotation = TestPropertySource.class,
attribute = "locations")
String[] propFiles() default {};
}
16
both declare locations attribute
explicit
explicit

Avoid Attribute Override Conflict w/ @AliasFor
(2)
@TransactionalTest(
xmlFiles = "/order-test-config.xml",
propFiles = "/order-test.properties"
)
public class OrderRepositoryTests {
}
17
@TestPropertySource

Embedded Databases – What’s in a Name?
Q: Why should I care what my embedded database is named?
A: Because you’ll run into problems if your DataSource config is imported from
multiple places within your test suite.
Q: Why? Doesn’t it just create a new instance of the database?
A: Recreating an embedded database within the same JVM doesn’t actually create
anything: a second attempt simply connects to the existing one.
Q: Ummmm… What?!
A: When you connect to an embedded database, it gets created if it doesn’t already
exist; otherwise, you just connect to the existing instance. Assigning each one a
unique name results in different JDBC connection URLs and thus different
instances.
18

Unique Names for Embedded Databases
19
• EmbeddedDatabaseBuilder
• setName() – since 3.0
• generateUniqueName() – since 4.2
• <jdbc:embedded-database>
• id – used as name since 3.0
o but bad since the id is usually “dataSource”... i.e., not unique
• database-name – since 4.2
• generate-name – since 4.2

Ex: Embedded Database in Java Config
20
@Bean
public DataSource dataSource() {
return new EmbeddedDatabaseBuilder()
.generateUniqueName(true)
.addScript("schema.sql")
.addScript("user_data.sql")
.build();
}
New in Spring 4.2

Ex: Embedded Database XML Config
21
<jdbc:embedded-database id="dataSource" generate-name="true">
<jdbc:script location="classpath:/schema.sql" />
<jdbc:script location="classpath:/user_data.sql" />
</jdbc:embedded-database>
New in Spring 4.2

Spring Cleaning
• @TransactionConfiguration
• Deprecated in 4.2
• @Rollback (and @Commit) now supported at the class level
• Use @Transactional qualifiers
• AssertThrows
• Deprecated in 3.x; gone in 4.2
• JUnit: use @Test(expected = ...) or @Rule ExpectedException
• TestNG: use @Test(expectedExceptions = ...)
22

Extension Points
• ContextCache
• Now a public API with DefaultContextCache implementation
• DefaultTestContext, DefaultBootstrapContext, and
DefaultCacheAwareContextLoaderDelegate
• Now public classes, allowing for custom extensions
• TestContextBootstrapper
• Now responsible for building the TestContext
23

Spring + JUnit … @Rules!
• SpringJUnit4ClassRunner
• Serving the community since Spring 2.5 (2007)
• But… can’t be used with other runners
o JUnit's Parameterized, MockitoJUnitRunner, etc.
• SpringClassRule & SpringMethodRule
• Since Spring 4.2
• Can be used with any JUnit runner!
• Have to be used together
• Provide full power of the Spring TestContext Framework
24

Ex: SpringClassRule & SpringMethodRule
25
@RunWith(Parameterized.class)
public class ParameterizedSpringRuleTests {
@ClassRule
public static final SpringClassRule SPRING_CLASS_RULE
= new SpringClassRule();
@Rule
public final SpringMethodRule springMethodRule
= new SpringMethodRule();

HtmlUnit, Selenium, & Geb
• First-class support for HtmlUnit and Selenium in Spring MVC Test
• Initially a stand-alone project
• Incorporated into spring-test in Spring 4.2
• Page-based web app testing w/o a Servlet container
• The Selenium support can also be used with Geb
26

MockMvc & HtmlUnit WebClient Setup
• spring-test (4.2+) & htmlunit (2.18+)
• MockMvcWebClientBuilder: several options, simplest case below
27
@Autowired WebApplicationContext wac;
WebClient webClient;
@Before
public void setup() {
webClient = MockMvcWebClientBuilder
.webAppContextSetup(wac).build();
}

MockMvc & Selenium WebDriver Setup
• spring-test (4.2+) & selenium-htmlunit-driver (2.47+)
• MockMvcHtmlUnitDriverBuilder: several options, simplest case below
28
@Autowired WebApplicationContext wac;
WebDriver webDriver;
@Before
public void setup() {
webDriver = MockMvcHtmlUnitDriverBuilder
.webAppContextSetup(wac).build();
}

Odds & Ends (1)
• ReflectionTestUtils
• Now you can get or set static fields, including constants
• AopTestUtils
• Obtain reference to target object hidden behind one or more Spring proxies
• Useful if your mock gets proxied (e.g., if your interface is @Transactional)
• @DirtiesContext
• New BEFORE_METHOD, BEFORE_CLASS, &
BEFORE_EACH_TEST_METHOD modes
• Requires DirtiesContextBeforeModesTestExecutionListener, enabled by
default
29

ReflectionTestUtils vs. Proper Design
• Proper design mandates that we use the most narrow visibility possible.
• But it’s sometimes meaningful to test private methods, or change values of
final fields, etc.
• As a work-around, set the visibility to package (no keyword) and put the test
class in the same package.
• Guava provides the @VisibleForTesting annotation to document this hack.
• ReflectionTestUtils is an alternative to such work-arounds that promotes proper
design.
30

Odds & Ends (2)
• @Commit
• Syntactical sugar for @Rollback(false)
• Inlined statements with @Sql
• When a dedicated SQL script is overkill
• Configured via the new statements attribute
• Executed after SQL scripts in same @Sql annotation
• Great for one-liners
• Spring MVC Test - MvcResult logging
• New log(), print(OutputStream), and print(Writer) methods in
MockMvcResultHandlers complement existing print() method
31

@Test
@Sql(statements = "DROP TABLE user IF EXISTS")
@Sql(
scripts = "/test-schema.sql",
statements = "INSERT INTO user VALUES ('Dilbert')"
)
public void userTest() {
// code that uses the test schema and test user
}
Ex: Inlined @Sql Statements

@Before
public void setUpMockMvc() {
mockMvc = MockMvcBuilders
.webAppContextSetup(wac)
.alwaysDo(print(System.err))
.build();
}
Ex: Logging MvcResult to STDERR

JUnit vs TestNG
34

JUnit
• De facto testing framework for Java
• Most popular library in the entire
Java ecosystem
• http://bit.ly/1iwwboO
35

JUnit
• Unit for… unit testing!
• Test methods are independent and isolated
• Simplicity can be both a pro and a con
• Can be used for integration testing, too
• Test methods are unordered
• Unless you use @FixMethodOrder
• Single Runner
• Spring OR Mockito OR Parameterized
• Rules to the rescue
36

TestNG
• Implemented test annotations before JUnit
• Richer lifecycle than JUnit
• Ordering and grouping of test methods
• Concurrent test execution
37

Spring Boot Tests
38

Integration Tests with Spring Boot
• @SpringApplicationConfiguration
• Like @ContextConfiguration but with SpringApplicationContextLoader
• Fully Loaded
• @IntegrationTest
o IntegrationTestPropertiesListener vs. @TestPropertySource
• @WebIntegrationTest
• Limit scope of auto-configuration
• @TestRepositoryConfig as example
39

Spring Security Tests
40

Spring Security Test Annotations
• WithSecurityContextTestExecutionListener
• auto-detected
• @WithMockUser
• See RestEventsControllerIT in spring-events
• @WithUserDetails
• @WithSecurityContext
41

Spring Security & MockMvc
• apply(springSecurity())
• with(...)
• user(...)
• authentication(...)
• securityContext(...)
• httpBasic(...)
• perform(...)
• formLogin()
• logout()
42

Testing Tips & Tricks
43

Eclipse
• Define key bindings for executing tests quickly
• Alt + Shift + X… T  too awkward to type frequently!
• Sam’s personal settings:
o Run JUnit Test  Ctrl + J
o Rerun JUnit Test  Ctrl + Shift + J
• Set up content assist favorites for common static imports
• org.junit.Assert OR org.assertj.core.api.Assertions
• org.mockito.Mockito
• org.springframework.test.web.servlet.request.MockMvcRequestBuilders
• org.springframework.test.web.servlet.result.MockMvcResultMatchers
44

Context Caching
• Granularity of context configuration files
• Goal: one entry point for production and one for testing
• But… not very practical: you’ll need to support different scenarios
• Too many constellations  too many contexts
• Too few constellations  all tests use the same config
• Optimum use of the context cache
• Avoid frequent use of @DirtiesContext
• Cache statistics are logged at DEBUG level for category
org.springframework.test.context.cache
45

Integration Tests: Spring Boot vs. Spring Core
• The key differences are speed and scope
• @SpringApplicationConfiguration vs. @ContextConfiguration
• @EnableAutoConfiguration vs. hand-crafted test @Configuration
• See @TestRepositoryConfig in spring-events app
46

Scope
• Think about the scope of your test
• SUT: Subject Under Test
• The larger the SUT, the smaller the
number of tests
• Mock or fake the dependencies of
your SUT
47

End-to-end Testing
• A few nominal scenarios
• Very brittle
• Use the Page pattern
• Decouples the page structure from the test itself
48

Integration Testing Challenges
• Speed
• Diagnosing the problem
• Brittleness
49

Speed
• Integration tests are often slow
• Execute unit tests before integration tests
• No need to run integration tests if unit tests fail
• Separate unit and integration tests in the build
• Maven: use the maven-failsafe-plugin
• Gradle: configure dependent Test tasks
o See spring-events for an example
50

Diagnosing the Problem
• Consider an e-commerce checkout process
• Multi-step use case
• Many places where things can go wrong
• Use small, focused, and aptly named methods
• Order and group methods
• According to the steps in the process
• Easy with TestNG; possible with JUnit
51

Brittleness
• All applications have infrastructure dependencies
• Database, web services, file system, time, etc.
• External dependencies might be unavailable during testing
• Sends a bad signal to developers
• Causes builds to fail intermittently
• Solution: approximate the production environment
• Mock or fake external dependencies
52

Developer & Test Databases
• Embedded databases
• HSQL, H2, Derby
• in-memory or persistent mode
• H2 supports compatibility modes for Oracle, MySQL, etc.
• Developer databases
• Use a single schema per developer if possible
• Be aware of the mismatch if you’re not using the same RDBMS in tests as in
production
53

Fake Remote Web Services with SoapUI &
Spark
• SOAP
• SoapUI has an API
• REST
• Spark
54
setPort(5678);
get("/hello", (request, response) -> {
return "Hello World!";
});

Mock Remote Web Services with Spring
• In-memory mocks for remote Web Service endpoints
• Don’t actually connect to a server over the network
• SOAP – Spring Web Services
• spring-ws-test module
• MockWebServiceServer
• REST – Spring MVC REST
• spring-test module
• MockRestServiceServer
55

DataSource pool exhaustion check
• Set the maximum number of connections in the pool to 1
• Tests blow up fast if connections are not returned to pool
56

Checking the database when a test fails
If a database related test is failing…
• Commit your transactions in your tests
• Via @Commit or the TestTransaction API
• Use a clean setup strategy
• Instead of a clean tear down strategy
• Use a file based database
• Use persistent storage mode for embedded DBs
• Inspect database state after failed test
57

Testing is about Saving Money
• Not about having more test coverage than your neighbor
• Think about ROI
58

JUnit Lambda
59

Give back to the project that’s given us so
much!
• JUnit is the de facto standard testing
framework in the Java ecosystem
• Last major release 10 years ago
• Times have changed: Java 8, etc.
• Introducing … JUnit Lambda … the
crowdfunding campaign to help make the
next major release of JUnit a reality
• Pitch in if you can, & help spread the word!
• @JUnitLambda
• https://www.indiegogo.com/projects/junit-lambda
60

In closing…
61

Spring Resources
Spring Framework
http://projects.spring.io/spring-framework
Spring Guides
http://spring.io/guides
Spring JIRA
https://jira.spring.io
Spring on GitHub
https://github.com/spring-projects/spring-framework
Stack Overflow
spring, spring-test, spring-mvc, spring-boot, spring-security, …
62

Blogs
Spring Blog
http://spring.io/blog
Swiftmind Blog
http://www.swiftmind.com/blog
Nicolas Fränkel’s Blog
https://blog.frankel.ch
63

Sam Brannen
@sam_brannen
www.slideshare.net/sbrannen
www.swiftmind.com
Learn More. Stay Connected.
@springcentral Spring.io/video Nicolas Fränkel
@nicolas_frankel

Get the Most out of Testing with Spring 4.2

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