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Contents
  1. 1. Assertions
  2. 2. Assumptions

Assertions

JUnit Jupiter 从Junit4 集成很多断言方法，还有新增一些java 8 lambda使用的。断言在静态方法 org.junit.jupiter.api.Assertions 类下面

测试用例分为几种情况
标准断言

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@Test
 void standardAssertions() {
     assertEquals(2, calculator.add(1, 1));
     assertEquals(4, calculator.multiply(2, 2),
             "The optional failure message is now the last parameter");
     assertTrue('a' < 'b', () -> "Assertion messages can be lazily evaluated -- "
             + "to avoid constructing complex messages unnecessarily.");
 }

分组断言，所有断言都执行，所有失败一起报告，assertAll

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@Test
void groupedAssertions() {
    // In a grouped assertion all assertions are executed, and all
    // failures will be reported together.
    assertAll("person",
        () -> assertEquals("Jane", person.getFirstName()),
        () -> assertEquals("Doe", person.getLastName())
    );
}

依赖断言，一个断言失败了，子代码被跳过

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@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("e"))
            );
        },
        () -> {
            // 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"))
            );
        }
    );
}

assertThrows 异常断言

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@Test
void exceptionTesting() {
    Exception exception = assertThrows(ArithmeticException.class, () ->
        calculator.divide(1, 0));
    assertEquals("/ by zero", exception.getMessage());
}

超时断言

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@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.
        new CountDownLatch(1).await();
    });
}

assertTimeoutPreemptively() 在不同的线程中计时，如果依赖ThreadLocal可能导致不可预期的副作用。

Assumptions

JUnit Jupiter 从Junit4 集成很多断言方法，还有新增一些java 8 lambda使用的。断言在静态方法 org.junit.jupiter.api.Assertions 类下面

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class AssumptionsDemo {

    private final Calculator calculator = new Calculator();

    @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, calculator.divide(4, 2));
            });

        // perform these assertions in all environments
        assertEquals(42, calculator.multiply(6, 7));
    }

}

Contents
  1. 1. Assertions
  2. 2. Assumptions