Denotes that a method is a test method. Unlike JUnit 4’s @Test annotation, this annotation does not declare any attributes, since test extensions in JUnit Jupiter operate based on their own dedicated annotations. Such methods are inherited unless they are overridden.
@ParameterizedTest
@RepeatedTest
@TestFactory
@TestInstance
@TestTemplate
@DisplayName
Declares a custom display name for the test class or test method. Such annotations are not inherited.
@BeforeEach
Denotes that the annotated method should be executed beforeeach@Test, @RepeatedTest, @ParameterizedTest, or @TestFactory method in the current class; analogous to JUnit 4’s @Before. Such methods are inherited unless they are overridden.
@AfterEach
Denotes that the annotated method should be executed aftereach@Test, @RepeatedTest, @ParameterizedTest, or @TestFactory method in the current class; analogous to JUnit 4’s @After. Such methods are inherited unless they are overridden.
@BeforeAll
@AfterAll
@Nested
@Tag
Used to declare tags for filtering tests, either at the class or method level; 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
Used to disable a test class or test method; analogous to JUnit 4’s @Ignore. Such annotations are not inherited.
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
@DisplayName("A special test case")
class JunitDisplayNameDemo {
@Test
@DisplayName("Custom test name containing spaces")
void testWithDisplayNameContainingSpaces() { }
@Test
@DisplayName("╯°□°)╯")
void testWithDisplayNameContainingSpecialCharacters() { }
@Test
@DisplayName("😱")
void testWithDisplayNameContainingEmoji() { }
}
3.3. 断言(Assertions)
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import static java.time.Duration.ofMillis;
import static java.time.Duration.ofMinutes;
import static org.junit.jupiter.api.Assertions.*;
class AssertionsDemo {
private static Person person;
@BeforeAll
public static void beforeAll() {
person = new Person("John", "Doe");
}
@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!";
}
}
3.4. 假想(Assumptions)
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assumptions.assumeTrue;
import static org.junit.jupiter.api.Assumptions.assumingThat;
import org.junit.jupiter.api.Test;
class AssumptionsDemo {
@Test
void testOnlyOnCiServer() {
assumeTrue("CI".equals(System.getenv("ENV")));
// remainder of test
}
@Test
void testOnlyOnDeveloperWorkstation() {
assumeTrue("DEV".equals(System.getenv("ENV")),
() -> "Aborting test: not on developer workstation");
// remainder of test
}
@Test
void testInAllEnvironments() {
assumingThat("CI".equals(System.getenv("ENV")),
() -> {
// perform these assertions only on the CI server
assertEquals(2, 2);
});
// perform these assertions in all environments
assertEquals("a string", "a string");
}
}
@ParameterizedTest
@ValueSource(strings = { "racecar", "radar", "able was I ere I saw elba" })
void palindromes(String candidate) {
assertTrue(isPalindrome(candidate));
}
4. 引用和引申
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Denotes that a method is a . Such methods are inherited unless they are overridden.
Denotes that a method is a test template for a . Such methods are inherited unless they are overridden.
Denotes that a method is a test factory for . Such methods are inherited unless they are overridden.
Used to configure the for the annotated test class. Such annotations are inherited.
Denotes that a method is a designed to be invoked multiple times depending on the number of invocation contexts returned by the registered . Such methods are inherited unless they are overridden.
Denotes that the annotated method should be executed beforeall@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" is used).
Denotes that the annotated method should be executed afterall@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" is used).
Denotes that the annotated class is a nested, non-static test class. @BeforeAll and @AfterAllmethods cannot be used directly in a @Nested test class unless the "per-class" is used. Such annotations are not inherited.
Used to register custom . Such annotations are inherited.