如何禁用特定测试用例的特定模拟？

Actually i have written 5 test cases for a particular method in a class. There is a statement in that method which calls a method from another class and i don't want to test that class so I have used a mock for that class. Now i want that while running the 5th test case it shouldn't visit that mocked class instead it should visit the original class. How to do it?Actually i have written 5 test cases for a part