Junit5断言

作者: 羋学僧 | 来源:发表于2022-08-25 08:52 被阅读0次

JUnit 5 断言是使用测试的实际结果验证预期结果。所有JUnit Jupiter 断言都是org.junit.jupiter.Assertions类中的静态方法，方便使用。

有异常的断言将抛出一个AssertionFailedError或它的一个子类

断言方法	描述
assertNull(java.lang.Object object)	检查对象是否为空
assertNotNull(java.lang. Object object)	检查对象是否不为空
assertEquals(long expected, long actual)	检查long类型的值是否相等
assertEquals(double expected , double actual, double delta)	检查指定精度的double值是否相等
assertFalse(boolean condition)	检查条件是否为假
assertTrue(boolean condition)	检查条件是否为真
assertSame(java.lang.Object expected, java.lang. Object actual)	检查两个对象引用是否引用同一对象（即对象是否相等)
assertNotSame(java.lang.Object unexpected, java.lang.Object actual)	检查两个对象引用是否不引用统一对象(即对象不等)

1、Assertions.assertEquals()和Assertions.assertNotEquals()示例

使用Assertions.assertEquals()断言期望值等于实际值。 assertEquals()针对不同的数据类型（例如， int，short，float，char等。它还支持传递的错误消息，以防万一测试失败。例如：

public static void assertEquals(int expected, int actual)
public static void assertEquals(int expected, int actual, String message)
public static void assertEquals(int expected, int actual, Supplier<String> messageSupplier)

void testCase() 
{
    //Test will pass
    Assertions.assertEquals(4, Calculator.add(2, 2));

    //Test will fail 
    Assertions.assertEquals(3, Calculator.add(2, 2), "Calculator.add(2, 2) test failed");

    //Test will fail 
    Supplier<String> messageSupplier  = ()-> "Calculator.add(2, 2) test failed";
    Assertions.assertEquals(3, Calculator.add(2, 2), messageSupplier);
}

类似地，Assertions.assertNotEquals()方法用于断言期望值不等于实际值。与assertEquals()相比，assertNotEquals()不会针对不同的数据类型重载方法，而仅接受Object。

public static void assertNotEquals(Object expected, Object actual)
public static void assertNotEquals(Object expected, Object actual, String message)
public static void assertNotEquals(Object expected, Object actual, Supplier<String> messageSupplier)

void testCase() 
{
    //Test will pass
    Assertions.assertNotEquals(3, Calculator.add(2, 2));

    //Test will fail 
    Assertions.assertNotEquals(4, Calculator.add(2, 2), "Calculator.add(2, 2) test failed");

    //Test will fail 
    Supplier<String> messageSupplier  = ()-> "Calculator.add(2, 2) test failed";
    Assertions.assertNotEquals(4, Calculator.add(2, 2), messageSupplier);
}

2、Assertions.assertArrayEquals()示例

与assertEquals()相似，assertArrayEquals()对数组执行相同的操作，即断言期望数组等于实际数组。它还具有针对不同数据类型的重载方法，例如boolean[]，char[]，int[]等。它还支持在测试失败的情况下传递要打印的错误消息。例如：

public static void assertArrayEquals(int[] expected, int[] actual)
public static void assertArrayEquals(int[] expected, int[] actual, String message)
public static void assertArrayEquals(int[] expected, int[] actual, Supplier<String> messageSupplier)

void testCase() 
{
    //Test will pass
    Assertions.assertArrayEquals(new int[]{1,2,3}, new int[]{1,2,3}, "Array Equal Test");

    //Test will fail because element order is different
    Assertions.assertArrayEquals(new int[]{1,2,3}, new int[]{1,3,2}, "Array Equal Test");

    //Test will fail because number of elements are different
    Assertions.assertArrayEquals(new int[]{1,2,3}, new int[]{1,2,3,4}, "Array Equal Test");
}

3、Assertions.assertIterableEquals()示例

它断言期望和实际的可迭代项高度相等。高度相等意味着集合中元素的数量和顺序必须相同；以及迭代元素必须相等。

它还有 3 种重载方法。

public static void assertIterableEquals(Iterable<?> expected, Iterable> actual)
public static void assertIterableEquals(Iterable<?> expected, Iterable> actual, String message)
public static void assertIterableEquals(Iterable<?> expected, Iterable> actual, Supplier<String> messageSupplier)

@Test
void testCase() 
{
     Iterable<Integer> listOne = new ArrayList<>(Arrays.asList(1,2,3,4));
     Iterable<Integer> listTwo = new ArrayList<>(Arrays.asList(1,2,3,4));
     Iterable<Integer> listThree = new ArrayList<>(Arrays.asList(1,2,3));
     Iterable<Integer> listFour = new ArrayList<>(Arrays.asList(1,2,4,3));

    //Test will pass
    Assertions.assertIterableEquals(listOne, listTwo);

    //Test will fail
    Assertions.assertIterableEquals(listOne, listThree);

    //Test will fail
    Assertions.assertIterableEquals(listOne, listFour);
}

4、Assertions.assertLinesMatch()示例

它断言期望的字符串列表与实际列表相匹配。将一个字符串与另一个字符串匹配的逻辑是：

检查expected.equals(actual) –如果是，则继续下一对
否则将expected视为正则表达式，并通过String.matches(String) 检查–如果是，则继续下一对
否则检查expected行是否为快进标记，如果是，则相应地应用快速前行并转到 1。

有效的快进标记是以>>开头和结尾并且至少包含 4 个字符的字符串。快进文字之间的任何字符都将被丢弃。

>>>>
>> stacktrace >>
>> single line, non Integer.parse()-able comment >>

5、Assertions.assertNotNull()和Assertions.assertNull()示例

assertNotNull()断言实际值不为空。类似地，assertNull()方法断言实际值为空。两者都有三种重载方法。

public static void assertNotNull(Object actual)
public static void assertNotNull(Object actual, String message)
public static void assertNotNull(Object actual, Supplier<String> messageSupplier)

public static void assertEquals(Object actual)
public static void assertEquals(Object actual, String message)
public static void assertEquals(Object actual, Supplier<String> messageSupplier)

@Test
void testCase() 
{    
    String nullString = null;
    String notNullString = "howtodoinjava.com";

    //Test will pass
    Assertions.assertNotNull(notNullString);

    //Test will fail
    Assertions.assertNotNull(nullString);

    //Test will pass
    Assertions.assertNull(nullString);

    // Test will fail
    Assertions.assertNull(notNullString);
}

6、Assertions.assertNotSame()和Assertions.assertSame()示例

assertNotSame()断言预期和实际不引用同一对象。同样，assertSame()方法断言，预期和实际引用完全相同的对象。两者都有三种重载方法。

public static void assertNotSame(Object actual)
public static void assertNotSame(Object actual, String message)
public static void assertNotSame(Object actual, Supplier<> messageSupplier)

public static void assertSame(Object actual)
public static void assertSame(Object actual, String message)
public static void assertSame(Object actual, Supplier<String> messageSupplier)

@Test
void testCase() 
{    
    String originalObject = "howtodoinjava.com";
    String cloneObject = originalObject;
    String otherObject = "example.com";

    //Test will pass
    Assertions.assertNotSame(originalObject, otherObject);

    //Test will fail
    Assertions.assertNotSame(originalObject, cloneObject);

    //Test will pass
    Assertions.assertSame(originalObject, cloneObject);

    // Test will fail
    Assertions.assertSame(originalObject, otherObject);
}

7、Assertions.assertTimeout()和Assertions.assertTimeoutPreemptively()示例

assertTimeout()和assertTimeoutPreemptively()均用于测试长时间运行的任务。如果测试用例中的给定任务花费的时间超过指定的持续时间，则测试将失败。

两种方法之间唯一的区别是assertTimeoutPreemptively()中的设置，如果超过超时，Executable或ThrowingSupplier的执行将被抢先中止。在assertTimeout()的情况下，不会中断Executable或ThrowingSupplier。

public static void assertTimeout(Duration timeout, Executable executable)
public static void assertTimeout(Duration timeout, Executable executable, String message)
public static void assertTimeout(Duration timeout, Executable executable, Supplier<String> messageSupplier)
public static void assertTimeout(Duration timeout, ThrowingSupplier<T> supplier, String message)
public static void assertTimeout(Duration timeout, ThrowingSupplier<T> supplier, Supplier<String> messageSupplier)

@Test
void testCase() {

    //This will pass
    Assertions.assertTimeout(Duration.ofMinutes(1), () -> {
        return "result";
    });

    //This will fail
    Assertions.assertTimeout(Duration.ofMillis(100), () -> {
        Thread.sleep(200);
        return "result";
    });

    //This will fail
    Assertions.assertTimeoutPreemptively(Duration.ofMillis(100), () -> {
        Thread.sleep(200);
        return "result";
    });
}

8、Assertions.assertTrue()和Assertions.assertFalse()示例

assertTrue()断言BooleanSupplier提供的条件为真。类似地，assertFalse()断言提供的条件为假。它具有以下重载方法：

public static void assertTrue(boolean condition)
public static void assertTrue(boolean condition, String message)
public static void assertTrue(boolean condition, Supplier<String> messageSupplier)
public static void assertTrue(BooleanSupplier booleanSupplier)
public static void assertTrue(BooleanSupplier booleanSupplier, String message)
public static void assertTrue(BooleanSupplier booleanSupplier, Supplier<String> messageSupplier)

public static void assertFalse(boolean condition)
public static void assertFalse(boolean condition, String message)
public static void assertFalse(boolean condition, Supplier<String> messageSupplier)
public static void assertFalse(BooleanSupplier booleanSupplier)
public static void assertFalse(BooleanSupplier booleanSupplier, String message)
public static void assertFalse(BooleanSupplier booleanSupplier, Supplier<String> messageSupplier)

@Test
void testCase() {

    boolean trueBool = true;
    boolean falseBool = false;

    Assertions.assertTrue(trueBool);
    Assertions.assertTrue(falseBool, "test execution message");
    Assertions.assertTrue(falseBool, AppTest::message);
    Assertions.assertTrue(AppTest::getResult, AppTest::message);

    Assertions.assertFalse(falseBool);
    Assertions.assertFalse(trueBool, "test execution message");
    Assertions.assertFalse(trueBool, AppTest::message);
    Assertions.assertFalse(AppTest::getResult, AppTest::message);
}

private static String message () {
    return "Test execution result";
}

private static boolean getResult () {
    return true;
}

9、Assertions.assertThrows()示例

它断言所提供的Executable的执行将引发expectedType的异常并返回该异常。

public static <T extends Throwable> T assertThrows(Class<T> expectedType, 
    Executable executable)

@Test
void testCase() {

    Throwable exception = Assertions.assertThrows(IllegalArgumentException.class, () -> {
        throw new IllegalArgumentException("error message");
    });
}

10、Assertions.fail()示例

fail()方法仅使测试失败。它具有以下重载方法：

public static void fail(String message)
public static void fail(Throwable cause)
public static void fail(String message, Throwable cause)
public static void fail(Supplier<String> messageSupplier)

public class AppTest {
    @Test
    void testCase() {

        Assertions.fail("not found good reason to pass");
        Assertions.fail(AppTest::message);
    }

    private static String message () {
        return "not found good reason to pass";
    }
}

Junit5断言

1、Assertions.assertEquals()和Assertions.assertNotEquals()示例

2、Assertions.assertArrayEquals()示例

3、Assertions.assertIterableEquals()示例

4、Assertions.assertLinesMatch()示例

5、Assertions.assertNotNull()和Assertions.assertNull()示例

6、Assertions.assertNotSame()和Assertions.assertSame()示例

7、Assertions.assertTimeout()和Assertions.assertTimeoutPreemptively()示例

8、Assertions.assertTrue()和Assertions.assertFalse()示例

9、Assertions.assertThrows()示例

10、Assertions.fail()示例

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