更简单的一行代码。使用Java 8和JUnit 5，本例不需要lambda表达式或花括号

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

@Test
void exceptionTesting() {

    assertThrows(MyException.class, myStackObject::doStackAction, "custom message if assertion fails..."); 

// note, no parenthesis on doStackAction ex ::pop NOT ::pop()
}

在Java 8和JUnit 5 (Jupiter)中，我们可以这样断言异常。 使用org.junit.jupiter.api.Assertions.assertThrows

public static < T extends Throwable > T assertThrows(类< T > expectedType， 可执行可执行) 断言所提供的可执行文件的执行将抛出expectedType的异常并返回该异常。 如果没有抛出异常，或者抛出了不同类型的异常，则此方法将失败。 如果您不想对异常实例执行额外的检查，只需忽略返回值。

@Test
public void itShouldThrowNullPointerExceptionWhenBlahBlah() {
    assertThrows(NullPointerException.class,
            ()->{
            //do whatever you want to do here
            //ex : objectName.thisMethodShoulThrowNullPointerExceptionForNullParameter(null);
            });
}

该方法将使用org.junit.jupiter.api中的函数接口可执行文件。

参考:

http://junit.org/junit5/docs/current/user-guide/#writing-tests-assertions http://junit.org/junit5/docs/5.0.0-M2/api/org/junit/jupiter/api/Executable.html http://junit.org/junit5/docs/5.0.0-M4/api/org/junit/jupiter/api/Assertions.html#assertThrows-java.lang.Class-org.junit.jupiter.api.function.Executable-

现在Junit5提供了一种断言异常的方法

您可以测试常规异常和定制异常

一般的异常场景:

ExpectGeneralException.java

public void validateParameters(Integer param ) {
    if (param == null) {
        throw new NullPointerException("Null parameters are not allowed");
    }
}

ExpectGeneralExceptionTest.java

@Test
@DisplayName("Test assert NullPointerException")
void testGeneralException(TestInfo testInfo) {
    final ExpectGeneralException generalEx = new ExpectGeneralException();

     NullPointerException exception = assertThrows(NullPointerException.class, () -> {
            generalEx.validateParameters(null);
        });
    assertEquals("Null parameters are not allowed", exception.getMessage());
}

您可以在这里找到一个测试CustomException的示例:断言异常代码示例

ExpectCustomException.java

public String constructErrorMessage(String... args) throws InvalidParameterCountException {
    if(args.length!=3) {
        throw new InvalidParameterCountException("Invalid parametercount: expected=3, passed="+args.length);
    }else {
        String message = "";
        for(String arg: args) {
            message += arg;
        }
        return message;
    }
}

ExpectCustomExceptionTest.java

@Test
@DisplayName("Test assert exception")
void testCustomException(TestInfo testInfo) {
    final ExpectCustomException expectEx = new ExpectCustomException();

     InvalidParameterCountException exception = assertThrows(InvalidParameterCountException.class, () -> {
            expectEx.constructErrorMessage("sample ","error");
        });
    assertEquals("Invalid parametercount: expected=3, passed=2", exception.getMessage());
}

This is what I do when testing to make sure an exception has been thrown

    
    //when
    final var tripConsumer = new BusTripConsumer(inputStream);
    final Executable executable = () -> tripConsumer.deserialiseTripData();

    //then
    assertThrows(IllegalArgumentException.class, executable);

您可以使用assertThrows()。我的例子取自文档http://junit.org/junit5/docs/current/user-guide/

import org.junit.jupiter.api.Test;

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

....

@Test
void exceptionTesting() {
    Throwable exception = assertThrows(IllegalArgumentException.class, () -> {
        throw new IllegalArgumentException("a message");
    });
    assertEquals("a message", exception.getMessage());
}

这里有一个简单的方法。

@Test
void exceptionTest() {

   try{
        model.someMethod("invalidInput");
        fail("Exception Expected!");
   }
   catch(SpecificException e){

        assertTrue(true);
   }
   catch(Exception e){
        fail("wrong exception thrown");
   }

}

它只有在抛出您期望的异常时才会成功。