Which of the following statements are true about JUnit5 tests?

a) Before executing a test, you should be sure about the context (values and conditions) of the objects used in this test.

b) In a JUnit test method, an exception thrown by the code under test always leads to an error.

c) A JUnit test case can proof that the code under test has no errors.

d) Several JUnit test class files may be created using/testing the same class under test.