collatz conjecture exercise w/ f-string method & no parentheses

python/collatz-conjecture/collatz_conjecture_test.py

@@ -0,0 +1,42 @@
+import unittest
+
+from collatz_conjecture import steps
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.2.1
+
+
+class CollatzConjectureTest(unittest.TestCase):
+    def test_zero_steps_for_one(self):
+        self.assertEqual(steps(1), 0)
+
+    def test_divide_if_even(self):
+        self.assertEqual(steps(16), 4)
+
+    def test_even_and_odd_steps(self):
+        self.assertEqual(steps(12), 9)
+
+    def test_large_number_of_even_and_odd_steps(self):
+        self.assertEqual(steps(1000000), 152)
+
+    def test_zero_is_an_error(self):
+        with self.assertRaisesWithMessage(ValueError):
+            steps(0)
+
+    def test_negative_value_is_an_error(self):
+        with self.assertRaisesWithMessage(ValueError):
+            steps(-15)
+
+    # Utility functions
+    def setUp(self):
+        try:
+            self.assertRaisesRegex
+        except AttributeError:
+            self.assertRaisesRegex = self.assertRaisesRegexp
+
+    def assertRaisesWithMessage(self, exception):
+        return self.assertRaisesRegex(exception, r".+")
+
+
+if __name__ == "__main__":
+    unittest.main()