java 如何在单元测试中覆盖被测试类调用的方法
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How to override a method in unit tests that is called from which the class being tested
提问by Khawar Ali
I am testing a class A's function func1.
我正在测试 A 类的函数 func1。
Func1 has a local variable of Class B and calls B's function func2. Code looks something like this:
Func1 有一个 B 类的局部变量，调用 B 的函数 func2。代码如下所示：
public Class A
{
public func1()
{
B object = new B();
int x = object.func2(something);
}
}
When I am testing func1 in its unit tests, I don't want func2 to get called.
当我在单元测试中测试 func1 时，我不希望 func2 被调用。
So I am trying to do something like this in the test:
所以我试图在测试中做这样的事情：
B textObject = new B()
{
@override
int func2(something)
{
return 5;
}
}
But it is still calling the func2 in the class B. Please suggest how to handle this.
但它仍然在调用 B 类中的 func2。请建议如何处理。
采纳答案by René Link
If you want to override the new B()constructor call - place it in an own method.
如果你想覆盖new B()构造函数调用 - 将它放在自己的方法中。
public Class A
{
public func1()
{
B object = newB();
int x = object.func2(something);
}
protected B newB(){
return new B();
}
}
In your test you can then override the Bconstructor call.
在您的测试中，您可以覆盖B构造函数调用。
public class APartitialMock extends A {
protected B newB(){
return new BMock();
}
}
public class BMock extends B {
int func2(something) {
return 5
}
}
Then use APartitialMockto test the func1with your kind of B.
然后使用APartitialMock来测试func1你的那种B。
PSIf you can or want to use a framework take a look at powermock - Mock Constructor
PS如果您可以或想要使用框架，请查看powermock - Mock Constructor
回答by krokodilko
I can make B as a class variable in A but that doesn't seem to help either. What would you suggest in this case?
我可以将 B 作为 A 中的类变量，但这似乎也无济于事。在这种情况下，您有什么建议？
If you make B as a class variable, then you can mock B, and "swap" it in the tested object of A.
Maybe not very elegant, but quick and simple.
An example:
如果你把 B 作为一个类变量，那么你可以模拟 B，并在 A 的测试对象中“交换”它。
也许不是很优雅，但快速简单。
一个例子：
public class B {
int func2(int something){
return 3*something;
}
}
public class A
{
// declare it as protected - a test need to have access to this field to replace it
protected B object = new B();
public int func1()
{
int x = object.func2(22);
return x;
}
}
And a test:
还有一个测试：
import static org.mockito.Mockito.*;
import static org.junit.Assert.*;
import org.junit.Test;
public class ATest {
@Test
public void test() {
A myA = new A();
B myB = mock(B.class);
// dummy function
when(myB.func2(anyInt())).thenReturn(20);
// replace B with mocked B
myA.object = myB;
int actual = myA.func1();
assertEquals(20, actual);
}
}
