从测试类B的方法调用测试类A的方法

I am using phpunit to unit test. In some test classes, I need to perform same tests that is already implemented in another test class.

So is it possible to call another test class's test method?

You can call a test method of another class. You can create an instance of the test class in the test and then call the method.

However, just because you can do something doesn't mean you should do something.

The use case that you are describing sounds like you have duplicated functionality. You should reconsider your design so that you do not need to do what you are describing. Your tests should be fairly small functions that are easy to follow. If you are reaching out to other test classes, your tests can become difficult to maintain, brittle, and hard to understand.