Mockito。如何基于模拟对象作为参数返回布尔值？

Question

Class A
{
public B makeB(int q)
    {
        return new B(q);
    }
    public boolean evaluate(int q)
    {
        B b = makeB(q);
        boolean result = b.get();
        return result;
    }
}

Class B
{
    int e;
    public B(int w)
    {
        e=w;
    }
    public boolean get()
    {
        //return boolean based on object B
    } 
}

Class ATest
{
    A a = spy(A.class);
    B b1 = mock(B.class);
    B b2 = mock(B.class);

    doReturn(b1).when(a).makeB(5);
    doReturn(b2).when(a).makeB(10);

    when(b1.get()).thenReturn(true);
    when(b2.get()).thenReturn(false);

    a.evaluate();
}

=======================

在这里，我想在对象B包含值5时从方法评估返回true，而在对象B包含值10时返回false。

B类来自外部库。

单元测试和模拟的新手。

Answer 1

The other answers are technically correct, but the first thing to understand: you should strive to not use a mocking framework like this.

Keep in mind: the purpose of a mocking framework is only to make testing possible/easier. Your mocking specs should be as simple as possible. Meaning: instead of thinking about having a mock giving different results on different parameters - the better solution is to have distinct tests and mocking specs, like:

@Test 
public void testFooWithA() {
  when(someMock.foo(eq(whateverA)).thenReturn(bar);
  ...

@Test 
public void testFooWithB() {
  when(someMock.foo(eq(whateverB)).thenReturn(somethingElse);
  ...

There are situations where you have write more sophisticated code to make your mocks "more smart". But most of the time when I had to do that - I stepped backed, and simplified my design under test. In other words: when your tests turn "too complicated" - most often the reason is a too complicated class/method under test.