Junit的异常测试

方式１：

@Test(expected = IndexOutOfBoundsException.class) 
public void empty() { 
     new ArrayList<Object>().get(0); 
}
解析：
＠Test的注释有一个可选参数expected，它作为Throwable的子类，可以抛出异常。

方式２：
使用try...catch()..

@Test
public void testExceptionMessage() {
    try {
        new ArrayList<Object>().get(0);
        fail("Expected an IndexOutOfBoundsException to be thrown");
    } catch (IndexOutOfBoundsException anIndexOutOfBoundsException) {
        assertThat(anIndexOutOfBoundsException.getMessage(), is("Index: 0, Size: 0"));
    }
}

方式３:
使用ExpectedException规则，此规则可以指示出异常和异常信息。

@Rule
public ExpectedException thrown = ExpectedException.none();

@Test
public void shouldTestExceptionMessage() throws IndexOutOfBoundsException {
    List<Object> list = new ArrayList<Object>();

    thrown.expect(IndexOutOfBoundsException.class);
    thrown.expectMessage("Index: 0, Size: 0");
    list.get(0); // execution will never get past this line
}

方式４：
使用Ｍatchers检查异常

import static org.hamcrest.Matchers.hasProperty;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.startsWith;

import javax.ws.rs.NotFoundException;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

public class TestExy {
    @Rule
    public ExpectedException thrown = ExpectedException.none();

    @Test
    public void shouldThrow() {
        TestThing testThing = new TestThing();
        thrown.expect(NotFoundException.class);
        thrown.expectMessage(startsWith("some Message"));
        thrown.expect(hasProperty("response", hasProperty("status", is(404))));
        testThing.chuck();
    }

    private class TestThing {
        public void chuck() {
            Response response = Response.status(Status.NOT_FOUND).entity("Resource not found").build();
            throw new NotFoundException("some Message", response);
        }
    }
}

更多信息点击此链接：
https://github.com/junit-team/junit4/wiki/Exception-testing