8 files declare their use of CourseTestBase in Course 3.x

CourseCommerceTest.php in modules/course_commerce/tests/src/Functional/CourseCommerceTest.php

CourseNodeTest.php in modules/course_node/tests/src/Functional/CourseNodeTest.php

CourseObjectBookTest.php in modules/course_book/tests/src/Functional/CourseObjectBookTest.php

CourseObjectContentTest.php in modules/course_content/tests/src/Functional/CourseObjectContentTest.php

CourseObjectNodeTest.php in modules/course_content/tests/src/Functional/CourseObjectNodeTest.php

CourseObjectQuizTest.php in modules/course_quiz/tests/src/Functional/CourseObjectQuizTest.php

CourseObjectUbercartTest.php in modules/course_uc/tests/src/Functional/CourseObjectUbercartTest.php

CourseObjectWebformTest.php in modules/course_webform/tests/src/Functional/CourseObjectWebformTest.php