write efficient tests with spring integration

1. 93 © VictorRentea.ro
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Integration Testing
with Spring
victor.rentea@gmail.com VictorRentea.ro @victorrentea

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Blog, Talks, Goodies on
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❤️ Simple Design, Refactoring, Unit Testing ❤️
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Unit Testing
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@victorrentea

4. 96 © VictorRentea.ro
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files
databases
queues
web services
Integration Tests
Failed Test Tolerance
If your test talks to and it fails,
is it a bug?
Probably not!😏
I hope not! 🙏
Tests failed
occasionally
some months after...

5. 97 © VictorRentea.ro
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Unit Tests
Integration
Deep
many layers
Fragile
DB, REST APIs, files
Fast
eg. 100 tests/sec
Slow
app startup,
network
... or Slow
in-mem DB, Spring,
Docker
failure ➔ maybe a bug
failure ➔ bug
Tiny
fine-grained
extensive mocks

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Zero Tolerance for Failed Tests

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🚨 USB device connected to Jenkins

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Let's Test a Search
Search Product
Name:
Supplier: IKEA
Search
...
DEV DB
eg Oracle
H2 in-memory
H2 standalone
DB in Docker
eg Oracle

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CODE

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@ActiveProfile("db-mem")
Toggle @Component, @Bean or @Configuration
Overrides properties with application-db-mem.properties

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Used to debug test
dependencies
Cleanup After Test
+10-60 wasted seconds
Spring
Don't push it to Jenkins!
@DirtiesContext
or
Manually
Before

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Isolated Repository Tests
@SpringBootTest
@RunWith(SpringRunner.class) // if on JUnit 4
public class TrainingServiceTest {
@Autowired
private TrainingRepo repo;
@Before/@BeforeEach
public void checkEmptyDatabase() {
assertThat(repo.findAll()).isEmpty();
}
@Test
public void getAll() {
...
repo.save(entity);
var results = repo.search(...);
assertEquals(...);
}
@DirtiesContext(methodMode = DirtiesContext.MethodMode.AFTER_METHOD)
Safest but wastes time
Use For: debugging
repo.deleteAll(); ... // others.deleteAll()… // in FK order
@Transactional Run each test in a Transaction,
rolled back after each test.
Use For: Relational DBs
In Large Apps:
Check that the state is clean
Manual Cleanup
Use For: non-transacted resources (eg files, nosql)

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If every test class is @Transactional
Can I still have problems?
YES
Intermediate COMMITs
aka nested transaction
@Transactional(REQUIRES_NEW)

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Inserting Test Data
repo.save()
in @Test
in @BeforeEach
in superclass
in @RegisterExtension (JUnit5)
Insert via @Profile
A Spring bean persisting data at app startup
src/test/resources/data.sql
(auto-inserted after src/test/resources/schema.sql creation)
@Sql
CascadeType.PERSIST
helps A LOT !

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Running SQL Scripts
@Sql
@Sql("data.sql")
@Sql({"schema.sql", "data.sql"})
On method or class
@SqlMergeMode
TestClass.testMethod.sql
before or after @Test
in the same transaction

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What DB to use in Tests
in-memory H2
(create schema via Hibernate)
Same DB in Local Docker
(create schema via scripts)
Personal Schema on Physical DB
(eg. REGLISS_VICTOR)
Shared Test Schema on Physical DB Legacy 500+ tables schemas
For PL/SQL, native features
For JPA + native standard SQL

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Invest hours, days, weeks
to
Make Your Test run on CI

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Assertions.*
assertThat(scoreStr).isEqualTo("Game won");
assertThat(list).anyMatch(e -> e.getX() == 1);
.doesNotContain(2);
.containsExactlyInAnyOrder(1,2,3);
.isEmpty();
assertThatThrownBy(() -> prod())
.hasMessageContaining("address");
+50 more
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
</dependency>
+60 more
Actual>Expected
Expected empty but was: <list.toString()>
Expressive Failure Message:
Testing Collections
Exceptions:
assertThat(list.stream().map(...))

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@txn
Feature: Records Search
Background:
Given Supplier "X" exists
Scenario Outline: Product Search
Given One product exists
And That product has name "<productName>"
When The search criteria name is "<searchName>"
Then That product is returned by search: "<returned>"
Examples:
| productName | searchName | returned |
| a | X | false |
| a | a | true |
Gherkin Language
wasted effort
if business never sees it
*
≈ @Before
= Separate transaction / test
.feature

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21. 120 © VictorRentea.ro
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@Bean
@Mock

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@Bean
@Mock
Replaces that bean with a Mockito Mock
Auto-reset() after each @Test

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Application Context is Reused
Starting Spring is slow.
Pro Tip:
Maximize Reuse
by test classes with the same:
@ActiveProfiles
@MockBean set
custom properties
locations= .xml
config classes= .class
more

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Faster Spring Tests
1. Tune JVM: -ea -noverify -mx2048m -XX:TieredStopAtLevel=1
Debugging Test Context reuse: logging.level.org.springframework.test.context.cache=DEBUG
4. Reuse Contexts: reduce no of Spring Banners on Jenkins
6. Disable/Limit Auto-Configuration
2. Lazy-Load only Tested Beans: spring.main.lazy-initialization=true
3. Disable Web: @SpringBootTest(webEnvironment = NONE)
https://stackoverflow.com/a/49663075
= +30 sec test run time
5. Run in parallel

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Reusing Test Context
@SpringBootTest
@Transactional
@ActiveProfiles({"db-mem", "test"})
public abstract class SpringTestBase {
@MockBean
protected FileRepo fileRepoMock;
... all @MockBeans ever needed
}
@ActiveProfiles("db-mem")
public class FeedProcessorWithMockTest
extends SpringTestBase {
@MockBean
when(fileRepoMock).then...
}
nothing requiring
dedicated context

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WireMock

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WireMock.stubFor(get(urlEqualTo("/some/thing"))
.withHeader("Accept", equalTo("text/xml"))
.willReturn(aResponse()
.withStatus(200)
.withHeader("Content-Type", "application/json")
.withBody("[{"id":12, "value":"WireMock"}]")));
B) Programmatically
{
"request": {
"method": "GET",
"url": "/some/thing"
},
"response": {
"status": 200,
"body": "Hello WireMock!",
"headers": {
"Content-Type": "text/plain"
}
}
}
A) via .json config files:
Templatize content
from a .json file on disk
Record them
from real systems
http://wiremock.org/docs/running-standalone/
WireMock

28. 138 © VictorRentea.ro
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My Application
SafetyClient
@MockBean
In-memory DB
(H2)
ProductRepo
Remote Sever
Real DB
@Transactional
WireMock
Local Docker
Real DB
.feature
What We've Covered
@DirtiesContext
ProductService
@Transactional

29. 139 © VictorRentea.ro
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files
databases
queues
web services
Integration Tests

30. 140 © VictorRentea.ro
a training by
Unit Tests
Integration
Deep
many layers
Fast
eg. 100 tests/sec
Slow
app startup,
network
... or Slow
in-mem DB, Spring,
Docker
Tiny
fine-grained
extensive mocks
Fragile
DB, REST APIs, files

31. Company Training:
victorrentea@gmail.com
Training for You:
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Thank You!
@victorrentea
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