Can anyone please provide me an example showing how to use the org.mockito.ArgumentCaptor
class and how it is different from simple matchers that are provided with mockito.
I read the provided mockito documents but those doesn't illustrate it clearly, none of them are able to explain it with clarity.
This question is related to
java
unit-testing
junit
mockito
The two main differences are:
ArgumentCaptor
can capture more than once.To illustrate the latter, say you have:
final ArgumentCaptor<Foo> captor = ArgumentCaptor.forClass(Foo.class);
verify(x, times(4)).someMethod(captor.capture()); // for instance
Then the captor will be able to give you access to all 4 arguments, which you can then perform assertions on separately.
This or any number of arguments in fact, since a VerificationMode
is not limited to a fixed number of invocations; in any event, the captor will give you access to all of them, if you wish.
This also has the benefit that such tests are (imho) much easier to write than having to implement your own ArgumentMatcher
s -- particularly if you combine mockito with assertj.
Oh, and please consider using TestNG instead of JUnit.
I agree with what @fge said, more over. Lets look at example. Consider you have a method:
class A {
public void foo(OtherClass other) {
SomeData data = new SomeData("Some inner data");
other.doSomething(data);
}
}
Now if you want to check the inner data you can use the captor:
// Create a mock of the OtherClass
OtherClass other = mock(OtherClass.class);
// Run the foo method with the mock
new A().foo(other);
// Capture the argument of the doSomething function
ArgumentCaptor<SomeData> captor = ArgumentCaptor.forClass(SomeData.class);
verify(other, times(1)).doSomething(captor.capture());
// Assert the argument
SomeData actual = captor.getValue();
assertEquals("Some inner data", actual.innerData);
Here I am giving you a proper example of one callback method . so suppose we have a method like method login() :
public void login() {
loginService = new LoginService();
loginService.login(loginProvider, new LoginListener() {
@Override
public void onLoginSuccess() {
loginService.getresult(true);
}
@Override
public void onLoginFaliure() {
loginService.getresult(false);
}
});
System.out.print("@@##### get called");
}
I also put all the helper class here to make the example more clear: loginService class
public class LoginService implements Login.getresult{
public void login(LoginProvider loginProvider,LoginListener callback){
String username = loginProvider.getUsername();
String pwd = loginProvider.getPassword();
if(username != null && pwd != null){
callback.onLoginSuccess();
}else{
callback.onLoginFaliure();
}
}
@Override
public void getresult(boolean value) {
System.out.print("login success"+value);
}}
and we have listener LoginListener as :
interface LoginListener {
void onLoginSuccess();
void onLoginFaliure();
}
now I just wanted to test the method login() of class Login
@Test
public void loginTest() throws Exception {
LoginService service = mock(LoginService.class);
LoginProvider provider = mock(LoginProvider.class);
whenNew(LoginProvider.class).withNoArguments().thenReturn(provider);
whenNew(LoginService.class).withNoArguments().thenReturn(service);
when(provider.getPassword()).thenReturn("pwd");
when(provider.getUsername()).thenReturn("username");
login.getLoginDetail("username","password");
verify(provider).setPassword("password");
verify(provider).setUsername("username");
verify(service).login(eq(provider),captor.capture());
LoginListener listener = captor.getValue();
listener.onLoginSuccess();
verify(service).getresult(true);
also dont forget to add annotation above the test class as
@RunWith(PowerMockRunner.class)
@PrepareForTest(Login.class)
The steps in order to make a full check are:
Prepare the captor :
ArgumentCaptor<SomeArgumentClass> someArgumentCaptor = ArgumentCaptor.forClass(SomeArgumentClass.class);
verify the call to dependent on component (collaborator of subject under test). times(1) is the default value, so ne need to add it.
verify(dependentOnComponent, times(1)).send(someArgumentCaptor.capture());
Get the argument passed to collaborator
SomeArgumentClass someArgument = messageCaptor.getValue();
someArgument can be used for assertions
Source: Stackoverflow.com