我已经用@Test注释编写了一些JUnit测试。如果我的测试方法抛出一个检查过的异常，并且如果我想断言该消息与异常一起，是否有一种方法可以使用JUnit @Test注释来做到这一点?AFAIK, JUnit 4.7不提供这个功能，但是将来的版本会提供吗?我知道在。net中你可以断言消息和异常类。在Java世界中寻找类似的特性。
这就是我想要的:
@Test (expected = RuntimeException.class, message = "Employee ID is null")
public void shouldThrowRuntimeExceptionWhenEmployeeIDisNull() {}
当前回答
@Test (expectedExceptions = ValidationException.class, expectedExceptionsMessageRegExp = "This is not allowed")
public void testInvalidValidation() throws Exception{
//test code
}
其他回答
在JUnit 4.13你可以做:
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThrows;
...
@Test
void exceptionTesting() {
IllegalArgumentException exception = assertThrows(
IllegalArgumentException.class,
() -> { throw new IllegalArgumentException("a message"); }
);
assertEquals("a message", exception.getMessage());
}
这也适用于JUnit 5，但有不同的导入:
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
...
@Test (expectedExceptions = ValidationException.class, expectedExceptionsMessageRegExp = "This is not allowed")
public void testInvalidValidation() throws Exception{
//test code
}
我喜欢user64141的回答，但发现它可以更一般化。以下是我的看法:
public abstract class ExpectedThrowableAsserter implements Runnable {
private final Class<? extends Throwable> throwableClass;
private final String expectedExceptionMessage;
protected ExpectedThrowableAsserter(Class<? extends Throwable> throwableClass, String expectedExceptionMessage) {
this.throwableClass = throwableClass;
this.expectedExceptionMessage = expectedExceptionMessage;
}
public final void run() {
try {
expectException();
} catch (Throwable e) {
assertTrue(String.format("Caught unexpected %s", e.getClass().getSimpleName()), throwableClass.isInstance(e));
assertEquals(String.format("%s caught, but unexpected message", throwableClass.getSimpleName()), expectedExceptionMessage, e.getMessage());
return;
}
fail(String.format("Expected %s, but no exception was thrown.", throwableClass.getSimpleName()));
}
protected abstract void expectException();
}
注意，在try块中保留“fail”语句会导致相关的断言异常被捕获;在catch语句中使用return可以防止这种情况。
你必须使用@Test(expected=SomeException.class)吗?当我们必须断言异常的实际消息时，这就是我们所做的。
@Test
public void myTestMethod()
{
try
{
final Integer employeeId = null;
new Employee(employeeId);
fail("Should have thrown SomeException but did not!");
}
catch( final SomeException e )
{
final String msg = "Employee ID is null";
assertEquals(msg, e.getMessage());
}
}
导入catch-exception库，并使用它。它比ExpectedException规则或try-catch规则干净得多。
他们文档中的例子:
import static com.googlecode.catchexception.CatchException.*;
import static com.googlecode.catchexception.apis.CatchExceptionHamcrestMatchers.*;
// given: an empty list
List myList = new ArrayList();
// when: we try to get the first element of the list
catchException(myList).get(1);
// then: we expect an IndexOutOfBoundsException with message "Index: 1, Size: 0"
assertThat(caughtException(),
allOf(
instanceOf(IndexOutOfBoundsException.class),
hasMessage("Index: 1, Size: 0"),
hasNoCause()
)
);
