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Check your assert declaration and the method implementation with the condition.
My guess is there is some kind of static state in the code being tested or in the test itself, so the tests aren't isolated. Adding the test changes the test order. In any case, your best course of action is to use the debugger to see why the tests fail.
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java.lang.AssertionError: Authentication failed when it should have succeeded: Certificate keyUsage constraint forbids SSL client authentication.