reuse result by configuring it at setUp()

Checklist:
- Invoke tearDown even if the test method fails
- Run multiple tests ✅

---

Output:
➜ python3 src/test_case_test.py
5 run, 0 failed

src/test_case_test.py

@@ -6,17 +6,18 @@
 
 
 class TestCaseTest(TestCase):
+    def setUp(self) -> None:
+        self.result = TestResult()
+
     def testTemplateMethod(self) -> None:
         test = WasRun("testMethod")
-        result = TestResult()
-        test.run(result)
-        assert ("1 run, 0 failed" == result.summary())
+        test.run(self.result)
+        assert ("1 run, 0 failed" == self.result.summary())
 
     def testFailedResult(self) -> None:
         test = WasRun("testBrokenMethod")
-        result = TestResult()
-        test.run(result)
-        assert ("1 run, 1 failed" == result.summary())
+        test.run(self.result)
+        assert ("1 run, 1 failed" == self.result.summary())
 
     def testFailedResultFormatting(self) -> None:
         result = TestResult()
@@ -26,17 +27,15 @@ def testFailedResultFormatting(self) -> None:
 
     def testFailedSetUp(self) -> None:
         test = TestCaseWithBrokenSetup("testMethod")
-        result = TestResult()
-        test.run(result)
-        assert ("1 run, 1 failed" == result.summary())
+        test.run(self.result)
+        assert ("1 run, 1 failed" == self.result.summary())
 
     def testSuite(self) -> None:
         suite = TestSuite()
         suite.add(WasRun("testMethod"))
         suite.add(WasRun("testBrokenMethod"))
-        result = TestResult()
-        suite.run(result)
-        assert ("2 run, 1 failed" == result.summary())
+        suite.run(self.result)
+        assert ("2 run, 1 failed" == self.result.summary())
 
 
 suite = TestSuite()