java - 如何为 IOException 编写 junit 测试用例

Question

我想检查 JUNIT 测试中的 IOException 类。这是我的代码:

public void loadProperties(String path) throws IOException {
  InputStream in = this.getClass().getResourceAsStream(path);
  Properties properties = new Properties();
  properties.load(in);
  this.foo = properties.getProperty("foo");
  this.foo1 = properties.getProperty("foo1");
}

当我尝试提供错误的属性文件路径时，它给出 NullPointerException。我想要对其进行 IOException 和 Junit 测试。非常感谢您的帮助。

Answer 1

试试这个

public TestSomeClass
{
    private SomeClass classToTest; // The type is the type that you are unit testing.

    @Rule
    public ExpectedException expectedException = ExpectedException.none();
    // This sets the rule to expect no exception by default.  change it in
    // test methods where you expect an exception (see the @Test below).

    @Test
    public void testxyz()
    {
        expectedException.expect(IOException.class);
        classToTest.loadProperties("blammy");
    }

    @Before
    public void preTestSetup()
    {
        classToTest = new SomeClass(); // initialize the classToTest
                                       // variable before each test.
    }
}

一些阅读: jUnit 4 Rule - 向下滚动到“ExpectedException Rules”部分。