introduce TestCaseWithBrokenTearDown class

This class will implement the scenario of a test case with a broken tearDown() method, which throws an exception every time it's ran.

Checklist:
- run tearDown even if the test fails 👈🏼

---

Output:
➜ python3 src/test_case_test.py
6 run, 1 failed

src/broken_teardown.py

@@ -0,0 +1,11 @@
+from test_case import TestCase
+
+class TestCaseWithBrokenTearDown(TestCase):
+    def __init__(self, name: str) -> None:
+        TestCase.__init__(self, name)
+
+    def testMethod(self) -> None:
+        pass
+
+    def tearDown(self) -> None:
+        raise Exception

src/test_case_test.py

@@ -3,6 +3,7 @@
 from test_result import TestResult
 from broken_setup import TestCaseWithBrokenSetup
 from test_suite import TestSuite
+from broken_teardown import TestCaseWithBrokenTearDown
 
 class TestCaseTest(TestCase):
     def setUp(self) -> None: