JUnit 5 ユーザーズガイドを読む 2

Table of Contents

JUnit 5 のユーザーズガイドを読みました。公式ドキュメントのうち、重要そうなところをピックアップしてまとめています。そのため公式ドキュメントにあってこちらにない文章もあります。

この記事はからの続きです。

3 テストを記述する

最初のテストケース (Kotlin)

import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Test
internal class FirstJUnit5Tests {
@Test
fun `my first test`() {
assertEquals(2, 1 + 1)
}
}

import org.junit.jupiter.api.Assertions.assertEquals

import org.junit.jupiter.api.Test

internal class FirstJUnit5Tests {

@Test

fun `my first test`() {

assertEquals(2, 1 + 1)

}

最初のテストケース (Java)

import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
class FirstJUnit5Tests {
@Test
void myFirstTest() {
assertEquals(2, 1 + 1);
}
}

import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.Test;

class FirstJUnit5Tests {

@Test

void myFirstTest() {

assertEquals(2, 1 + 1);

}

3.1 アノテーション

JUnit Jupiter では次のアノテーションを使って、テストの設定や、フレームワークの拡張ができます。

すべてのコアアノテーションは junit-jupiter-api の org.junit.jupiter.api パッケージにあります。

アノテーション	説明
`@Test`	関数がテスト用の関数であることを示します。 JUnit 4 の `@Test` アノテーションとは異なり、 this annotation does not declare any attributes, since test extensions in JUnit Jupiter operate based on their own dedicated annotations. オーバライドされない限り Such methods are inherited unless they are overridden.
`@ParameterizedTest`	メソッドがパラメタライズドテストであることを示します。 Such methods are inherited unless they are overridden.
`@RepeatedTest`	メソッドが Denotes that a method is a test template for a repeated test. Such methods are inherited unless they are overridden.
`@TestFactory`	Denotes that a method is a test factory for dynamic tests. Such methods are inherited unless they are overridden.
`@TestInstance`	Used to configure the test instance lifecycle for the annotated test class. Such annotations are inherited.
`@TestTemplate`	Denotes that a method is a template for test cases designed to be invoked multiple times depending on the number of invocation contexts returned by the registered providers. Such methods are inherited unless they are overridden.
`@DisplayName`	テストクラスおよびテストメソッドに、独自の表示名を設定します。 Such annotations are not inherited.
`@BeforeEach`	このアノテーションが付与されたメソッドは `@Test` または `@RepeatedTest`, `@ParameterizedTest`, `@TestFactory` でアノテートされたそれぞれのメソッドが実行される前に実行されます。 JUnit 4 での `@Before` に相当します。 Such methods are inherited unless they are overridden.
`@AfterEach`	このアノテーションが付与されたメソッドは `@Test` または `@ParameterizedTest`, `@TestFactory` でアノテートされたそれぞれのメソッドが実行された後に実行されます。 JUnit 4 での `@After` に相当します。 Such methods are inherited unless they are overridden.
`@BeforeAll`	Denotes that the annotated method should be executed before all @Test, @RepeatedTest, @ParameterizedTest, and @TestFactory methods in the current class; analogous to JUnit 4’s @BeforeClass. Such methods are inherited (unless they are hidden or overridden) and must be static (unless the “per-class” test instance lifecycle is used).
`@AfterAll`	Denotes that the annotated method should be executed after all @Test, @RepeatedTest, @ParameterizedTest, and @TestFactory methods in the current class; analogous to JUnit 4’s @AfterClass. Such methods are inherited (unless they are hidden or overridden) and must be static (unless the “per-class” test instance lifecycle is used).
`@Nested`	Denotes that the annotated class is a nested, non-static test class. @BeforeAll and @AfterAll methods cannot be used directly in a @Nested test class unless the “per-class” test instance lifecycle is used. Such annotations are not inherited.
`@Tag`	Used to declare tags for filtering tests, either at the class or method level; JUnit 4 でいうところの `TestNG`, `Categories` に相当します。 analogous to test groups in TestNG or Categories in JUnit 4. Such annotations are inherited at the class level but not at the method level.
`@Disabled`	テストクラス、テストメソッドを無効にする場合に使います。 JUnit 4 でいうところの `@Ignore` に相当します。 Such annotations are not inherited.
`@ExtendWith`	カスタム拡張を登録する場合に使います。 Used to register custom extensions. Such annotations are inherited.

3.1.1 メタアノテーションと合成アノテーション

JUnit Jupiter のアノテーションはメタアノテーションとして扱われるため、 JUnit Jupiter アノテーションのセマンティクスを継承した合成アノテーションを作成できます。

例えば @Tag("fast") をコピー&ペーストする代わりに、次のように独自の合成アノテーション @Fast を作成して利用できます。

Kotlin のサンプル

import java.lang.annotation.Retention
import java.lang.annotation.RetentionPolicy
import org.junit.jupiter.api.Tag
@Target(
AnnotationTarget.CLASS,
AnnotationTarget.FILE,
AnnotationTarget.FUNCTION,
AnnotationTarget.PROPERTY_GETTER,
AnnotationTarget.PROPERTY_SETTER
)
@Retention(RetentionPolicy.RUNTIME)
@Tag("fast")
annotation class Fast

import java.lang.annotation.Retention

import java.lang.annotation.RetentionPolicy

import org.junit.jupiter.api.Tag

@Target(

AnnotationTarget.CLASS,

AnnotationTarget.FILE,

AnnotationTarget.FUNCTION,

AnnotationTarget.PROPERTY_GETTER,

AnnotationTarget.PROPERTY_SETTER

)

@Retention(RetentionPolicy.RUNTIME)

@Tag("fast")

annotation class Fast

Java のサンプル

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.junit.jupiter.api.Tag;
@Target({ ElementType.TYPE, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Tag("fast")
public @interface Fast {
}

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import org.junit.jupiter.api.Tag;

@Target({ ElementType.TYPE, ElementType.METHOD })

@Retention(RetentionPolicy.RUNTIME)

@Tag("fast")

public @interface Fast {

}

3.2 テストクラスとメソッド

テストメソッド は次のアノテーションで直接またはメタアノテートされたインスタンスメソッドです。

@Test
@RepeatedTest
@ParameterizedTest
@TestFactory
@TestTemplate

トップレベルのクラスまたは静的メンバクラスで、少なくともひとつのテストメソッドを持っているものをテストクラスといいます。

標準的なテストクラス (Kotlin)

import org.junit.jupiter.api.Assertions.fail
import org.junit.jupiter.api.AfterAll
import org.junit.jupiter.api.AfterEach
import org.junit.jupiter.api.BeforeAll
import org.junit.jupiter.api.BeforeEach
import org.junit.jupiter.api.Disabled
import org.junit.jupiter.api.Test
internal class StandardTests {
@BeforeEach
fun init() {
}
@Test
fun `succeeding test`() {
}
@Test
fun `failing test`() {
fail<Any>("a failing test")
}
@Test
@Disabled("for demonstration purposes")
fun `skipped test`() {
// not executed
}
@AfterEach
fun tearDown() {
}
companion object {
@BeforeAll
fun initAll() {
}
@AfterAll
fun tearDownAll() {
}
}
}

import org.junit.jupiter.api.Assertions.fail

import org.junit.jupiter.api.AfterAll

import org.junit.jupiter.api.AfterEach

import org.junit.jupiter.api.BeforeAll

import org.junit.jupiter.api.BeforeEach

import org.junit.jupiter.api.Disabled

import org.junit.jupiter.api.Test

internal class StandardTests {

@BeforeEach

fun init() {

}

@Test

fun `succeeding test`() {

}

@Test

fun `failing test`() {

fail<Any>("a failing test")

}

@Test

@Disabled("for demonstration purposes")

fun `skipped test`() {

// not executed

}

@AfterEach

fun tearDown() {

}

companion object {

@BeforeAll

fun initAll() {

}

@AfterAll

fun tearDownAll() {

}

標準的なテストクラス (Java)

import static org.junit.jupiter.api.Assertions.fail;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;
class StandardTests {
@BeforeAll
static void initAll() {
}
@BeforeEach
void init() {
}
@Test
void succeedingTest() {
}
@Test
void failingTest() {
fail("a failing test");
}
@Test
@Disabled("for demonstration purposes")
void skippedTest() {
// not executed
}
@AfterEach
void tearDown() {
}
@AfterAll
static void tearDownAll() {
}
}

import static org.junit.jupiter.api.Assertions.fail;

import org.junit.jupiter.api.AfterAll;

import org.junit.jupiter.api.AfterEach;

import org.junit.jupiter.api.BeforeAll;

import org.junit.jupiter.api.BeforeEach;

import org.junit.jupiter.api.Disabled;

import org.junit.jupiter.api.Test;

class StandardTests {

@BeforeAll

static void initAll() {

}

@BeforeEach

void init() {

}

@Test

void succeedingTest() {

}

@Test

void failingTest() {

fail("a failing test");

}

@Test

@Disabled("for demonstration purposes")

void skippedTest() {

// not executed

}

@AfterEach

void tearDown() {

}

@AfterAll

static void tearDownAll() {

}

テストクラスもテストメソッドも、 public にする必要はありません。

3.3 表示名

テストクラスもテストメソッドも、独自に表示名を決めることができます。スペース、特殊文字、絵文字も使用可能です。その名前はテストランナーおよびテストレポートで表示されます。

コード例 (Kotlin)

import org.junit.jupiter.api.DisplayName
import org.junit.jupiter.api.Test
@DisplayName("A special test case")
internal class DisplayNameDemo {
@Test
@DisplayName("Custom test name containing spaces")
fun testWithDisplayNameContainingSpaces() {
}
@Test
@DisplayName("╯°□°）╯")
fun testWithDisplayNameContainingSpecialCharacters() {
}
@Test
@DisplayName("?")
fun testWithDisplayNameContainingEmoji() {
}
}

import org.junit.jupiter.api.DisplayName

import org.junit.jupiter.api.Test

@DisplayName("A special test case")

internal class DisplayNameDemo {

@Test

@DisplayName("Custom test name containing spaces")

fun testWithDisplayNameContainingSpaces() {

}

@Test

@DisplayName("╯°□°）╯")

fun testWithDisplayNameContainingSpecialCharacters() {

}

@Test

@DisplayName("?")

fun testWithDisplayNameContainingEmoji() {

}

コード例 (Java)

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
@DisplayName("A special test case")
class DisplayNameDemo {
@Test
@DisplayName("Custom test name containing spaces")
void testWithDisplayNameContainingSpaces() {
}
@Test
@DisplayName("╯°□°）╯")
void testWithDisplayNameContainingSpecialCharacters() {
}
@Test
@DisplayName("?")
void testWithDisplayNameContainingEmoji() {
}
}

import org.junit.jupiter.api.DisplayName;

import org.junit.jupiter.api.Test;

@DisplayName("A special test case")

class DisplayNameDemo {

@Test

@DisplayName("Custom test name containing spaces")

void testWithDisplayNameContainingSpaces() {

}

@Test

@DisplayName("╯°□°）╯")

void testWithDisplayNameContainingSpecialCharacters() {

}

@Test

@DisplayName("?")

void testWithDisplayNameContainingEmoji() {

}

IntelliJ IDEA のツールウィンドウでも表示されます。

IntelliJ IDEA のツールウィンドウでは、絵文字もそのまま表示されます。

ただ、 Gradle のコマンド ./gradlew test でテストを実行した場合、 Gradle の出力するレポートで絵文字は ?? として表示されます。

3.4 アサーション

JUnit Jupiter のアサーションには、 JUnit 4 にあったアサーションの多くと、 Java 8 のラムダと連携可能ないくつかのアサーションがあります。すべてのアサーションは org.junit.jupiter.api.Assertions クラスの静的メソッドです。

サンプルコード – Java

import static java.time.Duration.ofMillis;
import static java.time.Duration.ofMinutes;
import static org.junit.jupiter.api.Assertions.assertAll;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTimeout;
import static org.junit.jupiter.api.Assertions.assertTimeoutPreemptively;
import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.api.Test;
class AssertionsDemo {
@Test
void standardAssertions() {
assertEquals(2, 2);
assertEquals(4, 4, "The optional assertion message is now the last parameter.");
assertTrue('a' < 'b', () -> "Assertion messages can be lazily evaluated -- "
+ "to avoid constructing complex messages unnecessarily.");
}
@Test
void groupedAssertions() {
// In a grouped assertion all assertions are executed,
// and any failures will be reported together.
assertAll("person",
() -> assertEquals("John", person.getFirstName()),
() -> assertEquals("Doe", person.getLastName())
);
}
@Test
void dependentAssertions() {
// Within a code block, if an assertion fails the
// subsequent code in the same block will be skipped.
assertAll("properties",
() -> {
String firstName = person.getFirstName();
assertNotNull(firstName);
// Executed only if the previous assertion is valid.
assertAll("first name",
() -> assertTrue(firstName.startsWith("J")),
() -> assertTrue(firstName.endsWith("n"))
);
},
() -> {
// Grouped assertion, so processed independently
// of results of first name assertions.
String lastName = person.getLastName();
assertNotNull(lastName);
// Executed only if the previous assertion is valid.
assertAll("last name",
() -> assertTrue(lastName.startsWith("D")),
() -> assertTrue(lastName.endsWith("e"))
);
}
);
}
@Test
void exceptionTesting() {
Throwable exception = assertThrows(IllegalArgumentException.class, () -> {
throw new IllegalArgumentException("a message");
});
assertEquals("a message", exception.getMessage());
}
@Test
void timeoutNotExceeded() {
// The following assertion succeeds.
assertTimeout(ofMinutes(2), () -> {
// Perform task that takes less than 2 minutes.
});
}
@Test
void timeoutNotExceededWithResult() {
// The following assertion succeeds, and returns the supplied object.
String actualResult = assertTimeout(ofMinutes(2), () -> {
return "a result";
});
assertEquals("a result", actualResult);
}
@Test
void timeoutNotExceededWithMethod() {
// The following assertion invokes a method reference and returns an object.
String actualGreeting = assertTimeout(ofMinutes(2), AssertionsDemo::greeting);
assertEquals("Hello, World!", actualGreeting);
}
@Test
void timeoutExceeded() {
// The following assertion fails with an error message similar to:
// execution exceeded timeout of 10 ms by 91 ms
assertTimeout(ofMillis(10), () -> {
// Simulate task that takes more than 10 ms.
Thread.sleep(100);
});
}
@Test
void timeoutExceededWithPreemptiveTermination() {
// The following assertion fails with an error message similar to:
// execution timed out after 10 ms
assertTimeoutPreemptively(ofMillis(10), () -> {
// Simulate task that takes more than 10 ms.
Thread.sleep(100);
});
}
private static String greeting() {
return "Hello, World!";
}
}

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import static java.time.Duration.ofMillis;

import static java.time.Duration.ofMinutes;

import static org.junit.jupiter.api.Assertions.assertAll;

import static org.junit.jupiter.api.Assertions.assertEquals;

import static org.junit.jupiter.api.Assertions.assertNotNull;

import static org.junit.jupiter.api.Assertions.assertThrows;

import static org.junit.jupiter.api.Assertions.assertTimeout;

import static org.junit.jupiter.api.Assertions.assertTimeoutPreemptively;

import static org.junit.jupiter.api.Assertions.assertTrue;

import org.junit.jupiter.api.Test;

class AssertionsDemo {

@Test

void standardAssertions() {

assertEquals(2, 2);

assertEquals(4, 4, "The optional assertion message is now the last parameter.");

assertTrue('a' < 'b', () -> "Assertion messages can be lazily evaluated -- "

+ "to avoid constructing complex messages unnecessarily.");

}

@Test

void groupedAssertions() {

// In a grouped assertion all assertions are executed,

// and any failures will be reported together.

assertAll("person",

() -> assertEquals("John", person.getFirstName()),

() -> assertEquals("Doe", person.getLastName())

);

}

@Test

void dependentAssertions() {

// Within a code block, if an assertion fails the

// subsequent code in the same block will be skipped.

assertAll("properties",

() -> {

String firstName = person.getFirstName();

assertNotNull(firstName);

// Executed only if the previous assertion is valid.

assertAll("first name",

() -> assertTrue(firstName.startsWith("J")),

() -> assertTrue(firstName.endsWith("n"))

);

() -> {

// Grouped assertion, so processed independently

// of results of first name assertions.

String lastName = person.getLastName();

assertNotNull(lastName);

// Executed only if the previous assertion is valid.

assertAll("last name",

() -> assertTrue(lastName.startsWith("D")),

() -> assertTrue(lastName.endsWith("e"))

);

}

);

}

@Test

void exceptionTesting() {

Throwable exception = assertThrows(IllegalArgumentException.class, () -> {

throw new IllegalArgumentException("a message");

});

assertEquals("a message", exception.getMessage());

}

@Test

void timeoutNotExceeded() {

// The following assertion succeeds.

assertTimeout(ofMinutes(2), () -> {

// Perform task that takes less than 2 minutes.

});

}

@Test

void timeoutNotExceededWithResult() {

// The following assertion succeeds, and returns the supplied object.

String actualResult = assertTimeout(ofMinutes(2), () -> {

return "a result";

});

assertEquals("a result", actualResult);

}

@Test

void timeoutNotExceededWithMethod() {

// The following assertion invokes a method reference and returns an object.

String actualGreeting = assertTimeout(ofMinutes(2), AssertionsDemo::greeting);

assertEquals("Hello, World!", actualGreeting);

}

@Test

void timeoutExceeded() {

// The following assertion fails with an error message similar to:

// execution exceeded timeout of 10 ms by 91 ms

assertTimeout(ofMillis(10), () -> {

// Simulate task that takes more than 10 ms.

Thread.sleep(100);

});

}

@Test

void timeoutExceededWithPreemptiveTermination() {

// The following assertion fails with an error message similar to:

// execution timed out after 10 ms

assertTimeoutPreemptively(ofMillis(10), () -> {

// Simulate task that takes more than 10 ms.

Thread.sleep(100);

});

}

private static String greeting() {

return "Hello, World!";

}

JUnit Jupiter は Kotlin とうまく連携するアサーションも備えています。すべての JUnit Jupiter Kotlin アサーションは org.junit.jupiter.api パッケージのトップレベル関数です。たとえば assertAll は、 Java のコードでは org.junit.jupiter.api.Assertions.assertAll を使っていましたが、 Kotlin では Kotlin で使いやすいようにカスタマイズされている org.junit.jupiter.api.assertAll を使います。もちろん、 org.junit.jupiter.api.Assertions.assertAll も利用可能です。 (関連: Qiita記事: JUnit 5 assertAll)

次のサンプルコードで、下の2つのテストメソッドは、 Kotlin のサンプルにのみあるテストメソッドです。

サンプルコード (Kotlin)

import java.time.Duration.ofMillis
import java.time.Duration.ofMinutes
import org.junit.jupiter.api.assertAll
import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Assertions.assertNotNull
import org.junit.jupiter.api.assertThrows
import org.junit.jupiter.api.Assertions.assertTimeout
import org.junit.jupiter.api.Assertions.assertTimeoutPreemptively
import org.junit.jupiter.api.Assertions.assertTrue
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.function.ThrowingSupplier
internal class AssertionsDemo {
companion object {
data class Person(
val firstName: String,
val lastName: String
)
val person = Person(
"John",
"Doe"
)
val people = listOf(person, person)
}
@Test
fun `standard assertions`() {
assertEquals(2, 2)
assertEquals(
4,
4,
"The optional assertion message " +
"is now the last parameter."
)
assertTrue('a' < 'b') {
"Assertion messages can be lazily evaluated -- " +
"to avoid constructing complex messages " +
"unnecessarily."
}
}
@Test
fun `grouped assertions`() {
// In a grouped assertion all assertions are executed,
// and any failures will be reported together.
assertAll("person",
{ assertEquals("John", person.firstName) },
{ assertEquals("Doe", person.lastName) }
)
}
@Test
fun `dependent assertions`() {
// Within a code block, if an assertion fails the
// subsequent code in the same block will be skipped.
assertAll("properties",
{
val firstName = person.firstName
assertNotNull(firstName)
// Executed
// only if the previous assertion is valid.
assertAll("first name",
{ assertTrue(firstName.startsWith("J")) },
{ assertTrue(firstName.endsWith("n")) }
)
},
{
// Grouped assertion,
// so processed independently
// of results of first name assertions.
val lastName = person.lastName
assertNotNull(lastName)
// Executed
// only if the previous assertion is valid.
assertAll("last name",
{ assertTrue(lastName.startsWith("D")) },
{ assertTrue(lastName.endsWith("e")) }
)
}
)
}
@Test
fun `exception testing`() {
val exception =
assertThrows<IllegalArgumentException>(
"Should throw an exception"
) {
throw IllegalArgumentException("a message")
}
assertEquals("a message", exception.message)
}
@Test
fun `timeout not exceeded`() {
// The following assertion succeeds.
assertTimeout(ofMinutes(2)) {
// Perform task that takes less than 2 minutes.
}
}
@Test
fun `timeout not exceeded with result`() {
// The following assertion succeeds,
// and returns the supplied object.
val actualResult = assertTimeout<String>(
ofMinutes(2)
) { "a result" }
assertEquals("a result", actualResult)
}
@Test
fun `timeout not exceeded with method`() {
// The following assertion invokes
// a method reference and returns an object.
val actualGreeting = assertTimeout<String>(
ofMinutes(2),
ThrowingSupplier<String> { greeting() })
assertEquals("Hello, World!", actualGreeting)
}
@Test
fun `timeout exceeded`() {
// The following assertion fails
// with an error message similar to:
// execution exceeded timeout of 10 ms by 91 ms
assertTimeout(ofMillis(10)) {
// Simulate task that takes more than 10 ms.
Thread.sleep(100)
}
}
@Test
fun `timeout exceeded with preemptive termination`() {
// The following assertion fails
// with an error message similar to:
// execution timed out after 10 ms
assertTimeoutPreemptively(ofMillis(10)) {
// Simulate task that takes more than 10 ms.
Thread.sleep(100)
}
}
@Test
fun `assertions from a stream`() {
assertAll(
"people with name starting with J",
people
.stream()
.map {
// This mapping returns Stream<() -> Unit>
{ 
assertTrue(
it.firstName.startsWith("J"))
}
}
)
}
@Test
fun `assertions from a collection`() {
assertAll(
"people with last name of Doe",
people.map { { assertEquals("Doe", it.lastName) } }
)
}
private fun `greeting`(): String {
return "Hello, World!"
}
}

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import java.time.Duration.ofMillis

import java.time.Duration.ofMinutes

import org.junit.jupiter.api.assertAll

import org.junit.jupiter.api.Assertions.assertEquals

import org.junit.jupiter.api.Assertions.assertNotNull

import org.junit.jupiter.api.assertThrows

import org.junit.jupiter.api.Assertions.assertTimeout

import org.junit.jupiter.api.Assertions.assertTimeoutPreemptively

import org.junit.jupiter.api.Assertions.assertTrue

import org.junit.jupiter.api.Test

import org.junit.jupiter.api.function.ThrowingSupplier

internal class AssertionsDemo {

companion object {

data class Person(

val firstName: String,

val lastName: String

)

val person = Person(

"John",

"Doe"

)

val people = listOf(person, person)

}

@Test

fun `standard assertions`() {

assertEquals(2, 2)

assertEquals(

"The optional assertion message " +

"is now the last parameter."

)

assertTrue('a' < 'b') {

"Assertion messages can be lazily evaluated -- " +

"to avoid constructing complex messages " +

"unnecessarily."

}

@Test

fun `grouped assertions`() {

// In a grouped assertion all assertions are executed,

// and any failures will be reported together.

assertAll("person",

{ assertEquals("John", person.firstName) },

{ assertEquals("Doe", person.lastName) }

)

}

@Test

fun `dependent assertions`() {

// Within a code block, if an assertion fails the

// subsequent code in the same block will be skipped.

assertAll("properties",

{

val firstName = person.firstName

assertNotNull(firstName)

// Executed

// only if the previous assertion is valid.

assertAll("first name",

{ assertTrue(firstName.startsWith("J")) },

{ assertTrue(firstName.endsWith("n")) }

)

{

// Grouped assertion,

// so processed independently

// of results of first name assertions.

val lastName = person.lastName

assertNotNull(lastName)

// Executed

// only if the previous assertion is valid.

assertAll("last name",

{ assertTrue(lastName.startsWith("D")) },

{ assertTrue(lastName.endsWith("e")) }

)

}

)

}

@Test

fun `exception testing`() {

val exception =

assertThrows<IllegalArgumentException>(

"Should throw an exception"

) {

throw IllegalArgumentException("a message")

}

assertEquals("a message", exception.message)

}

@Test

fun `timeout not exceeded`() {

// The following assertion succeeds.

assertTimeout(ofMinutes(2)) {

// Perform task that takes less than 2 minutes.

}

@Test

fun `timeout not exceeded with result`() {

// The following assertion succeeds,

// and returns the supplied object.

val actualResult = assertTimeout<String>(

ofMinutes(2)

) { "a result" }

assertEquals("a result", actualResult)

}

@Test

fun `timeout not exceeded with method`() {

// The following assertion invokes

// a method reference and returns an object.

val actualGreeting = assertTimeout<String>(

ofMinutes(2),

ThrowingSupplier<String> { greeting() })

assertEquals("Hello, World!", actualGreeting)

}

@Test

fun `timeout exceeded`() {

// The following assertion fails

// with an error message similar to:

// execution exceeded timeout of 10 ms by 91 ms

assertTimeout(ofMillis(10)) {

// Simulate task that takes more than 10 ms.

Thread.sleep(100)

}

@Test

fun `timeout exceeded with preemptive termination`() {

// The following assertion fails

// with an error message similar to:

// execution timed out after 10 ms

assertTimeoutPreemptively(ofMillis(10)) {

// Simulate task that takes more than 10 ms.

Thread.sleep(100)

}

@Test

fun `assertions from a stream`() {

assertAll(

"people with name starting with J",

people

.stream()

.map {

// This mapping returns Stream<() -> Unit>

{

assertTrue(

it.firstName.startsWith("J"))

}

)

}

@Test

fun `assertions from a collection`() {

assertAll(

"people with last name of Doe",

people.map { { assertEquals("Doe", it.lastName) } }

)

}

private fun `greeting`(): String {

return "Hello, World!"

}

The Life

JUnit 5 ユーザーズガイドを読む 2

3 テストを記述する

3.1 アノテーション

3.1.1 メタアノテーションと合成アノテーション

3.2 テストクラスとメソッド

3.3 表示名

3.4 アサーション

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