java - 模拟 private void 方法给出 AssertionError

Question

我正在使用 Powermock 为 Jersey Web 服务构建测试用例，并尝试模拟数据库函数调用，特别是 PUT 和 POST 调用。但是，我在使其正常工作时遇到问题。

以下是其中一个 Web 服务调用的样子:

@Path("/v1.0.0")
public class WebService {

    @POST
    @Path("application")
    @Consumes(MediaType.APPLICATION_JSON)
    public Response createApplication(@QueryParam("callback") String callbackFunction, String body)
            throws NamingException, SQLException, IllegalStateException, CacheException, UnknownHostException,
            IOException {
        String query = "exec spInsertApplication ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?";
        String[] params = new String[16];
        JSONObject json = (JSONObject) JSONValue.parse(body);
        params[0] = json.get("name").toString();
        params[4] = json.get("software").toString();
        params[14] = json.get("customerid").toString();
        //Null checks for other params

        runUpdateQuery(query, params);

        return generateResponse(callbackFunction, null);
    }

    private void runUpdateQuery(String query, String[] queryParameters) {
        //Handles running DB query
    }
}

我的测试用例目前的样子:

@RunWith(PowerMockRunner.class)
@PrepareForTest(WebService.class)
@PowerMockIgnore( {"javax.management.*"}) 
public class TestRestWebService {

    @Test
    public void test_createApplication_returns_http_success() throws Exception {
        String query = "exec spInsertApplication ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?";
        String[] params = new String[16];
        params[0] = "test_app_name";
        params[4] = "test_software";
        params[14] = "23";

        WebService tested = createPartialMockAndInvokeDefaultConstructor(WebService.class, "runUpdateQuery");
        expectPrivate(tested, "runUpdateQuery", query, params).andAnswer(
                new IAnswer<Void>() {
                    @Override
                    public Void answer() throws Throwable {
                        return null;
                    }
                });
        replay(tested);

        String JSONString = "{\"name\":\"test_service_name\",\"software\":\"test_software\",\"customerid\":\"23\"}";
        Response output = tested.createApplication("CALLBACK", JSONString);
        verify(tested);
        assertTrue(output.getStatus() == 200);
    }
}

运行时，这会给我一个断言错误:

Unexpected method call WebService.runUpdateQuery("exec spInsertApplication ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?", ["test_service_name", null, null, null, "test_software", null, null, null, null, null, null, null, null, null, "23", null]):

WebService.runUpdateQuery("exec spInsertApplication ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?", ["test_service_name", null, null, null, "test_software", null, null, null, null, null, null, null, null, null, "23", null]): expected: 1, actual: 0

经过进一步挖掘，我发现原因很可能与 PowerMock 比较字符串数组的方式有关。因此，我还尝试采用更通用的方法，因为该函数无论如何都会返回 void，通过使用 EasyMock.anyString() 和 EasyMock.isA(String[].class) 代替我的两个参数，但这会导致 NullPointerException 。以下是该堆栈跟踪的前几行:

java.lang.NullPointerException
    at java.lang.Class.isAssignableFrom(Native Method)
    at org.powermock.reflect.internal.WhiteboxImpl.checkIfParameterTypesAreSame(WhiteboxImpl.java:2432)
    at org.powermock.reflect.internal.WhiteboxImpl.getMethods(WhiteboxImpl.java:1934)
    at org.powermock.reflect.internal.WhiteboxImpl.getBestMethodCandidate(WhiteboxImpl.java:1025)
    at org.powermock.reflect.internal.WhiteboxImpl.findMethodOrThrowException(WhiteboxImpl.java:948)

如何正确模拟此私有(private) void 方法以避免测试期间的数据库调用？

Answer 1

在深入研究此测试和文档几次后，我发现 expectPrivate 调用找不到我的方法。所以我发现我可以指定该函数，如下:

expectPrivate(tested, WebService.class.getDeclaredMethod("runUpdateQuery", String.class, String[].class),
        EasyMock.anyString(), EasyMock.aryEq(params)).andAnswer(new IAnswer<Void>() {
    @Override
    public Void answer() throws Throwable {
        return null;
    }
});

这还允许我在使用泛型类型定义函数时与函数调用的数组进行比较，就像我最初想要的那样。