feat: migrate misc tests

[dtopuzov]

Migrated tests:

• autocomplete
• error reporting
• setup
• version

Features in core:

• Fix get class name
• Enable creating test classes based on TnsTests without specifying setUp and tearDown methods

How tests was looking before:

class MyTestClass(TnsTest):

    @classmethod
    def setUpClass(cls):
        TnsTest.setUpClass()

    def setUp(self):
        TnsTest.setUp(self)

   def tearDown(self):
        TnsTest.tearDown(self)

    @classmethod
    def tearDownClass(cls):
        TnsTest.tearDownClass()

    def test_hello(self):
        pass

Example how simple test can look like now (and hooks in base class are still executed):

class MyTestClass(TnsTest):

    def test_hello(self):
        pass