chore: pytestify exponential_backoff (#1727)

Co-authored-by: Jordan Woods <[email protected]>

Author: jorwoods

test/test_exponential_backoff.py

@@ -1,60 +1,62 @@
-import unittest
+import pytest
 
 from tableauserverclient.exponential_backoff import ExponentialBackoffTimer
 from ._utils import mocked_time
 
 
-class ExponentialBackoffTests(unittest.TestCase):
-    def test_exponential(self):
-        with mocked_time() as mock_time:
-            exponentialBackoff = ExponentialBackoffTimer()
-            # The creation of our mock shouldn't sleep
-            self.assertAlmostEqual(mock_time(), 0)
-            # The first sleep sleeps for a rather short time, the following sleeps become longer
-            exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 0.5)
+def test_exponential() -> None:
+    with mocked_time() as mock_time:
+        exponentialBackoff = ExponentialBackoffTimer()
+        # The creation of our mock shouldn't sleep
+        pytest.approx(mock_time(), 0)
+        # The first sleep sleeps for a rather short time, the following sleeps become longer
+        exponentialBackoff.sleep()
+        pytest.approx(mock_time(), 0.5)
+        exponentialBackoff.sleep()
+        pytest.approx(mock_time(), 1.2)
+        exponentialBackoff.sleep()
+        pytest.approx(mock_time(), 2.18)
+        exponentialBackoff.sleep()
+        pytest.approx(mock_time(), 3.552)
+        exponentialBackoff.sleep()
+        pytest.approx(mock_time(), 5.4728)
+
+
+def test_exponential_saturation() -> None:
+    with mocked_time() as mock_time:
+        exponentialBackoff = ExponentialBackoffTimer()
+        for _ in range(99):
             exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 1.2)
+        # We don't increase the sleep time above 30 seconds.
+        # Otherwise, the exponential sleep time could easily
+        # reach minutes or even hours between polls
+        for _ in range(5):
+            s = mock_time()
             exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 2.18)
+            slept = mock_time() - s
+            pytest.approx(slept, 30)
+
+
+def test_timeout() -> None:
+    with mocked_time() as mock_time:
+        exponentialBackoff = ExponentialBackoffTimer(timeout=4.5)
+        for _ in range(4):
             exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 3.552)
+        pytest.approx(mock_time(), 3.552)
+        # Usually, the following sleep would sleep until 5.5, but due to
+        # the timeout we wait less; thereby we make sure to take the timeout
+        # into account as good as possible
+        exponentialBackoff.sleep()
+        pytest.approx(mock_time(), 4.5)
+        # The next call to `sleep` will raise a TimeoutError
+        with pytest.raises(TimeoutError):
             exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 5.4728)
-
-    def test_exponential_saturation(self):
-        with mocked_time() as mock_time:
-            exponentialBackoff = ExponentialBackoffTimer()
-            for _ in range(99):
-                exponentialBackoff.sleep()
-            # We don't increase the sleep time above 30 seconds.
-            # Otherwise, the exponential sleep time could easily
-            # reach minutes or even hours between polls
-            for _ in range(5):
-                s = mock_time()
-                exponentialBackoff.sleep()
-                slept = mock_time() - s
-                self.assertAlmostEqual(slept, 30)
-
-    def test_timeout(self):
-        with mocked_time() as mock_time:
-            exponentialBackoff = ExponentialBackoffTimer(timeout=4.5)
-            for _ in range(4):
-                exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 3.552)
-            # Usually, the following sleep would sleep until 5.5, but due to
-            # the timeout we wait less; thereby we make sure to take the timeout
-            # into account as good as possible
+
+
+def test_timeout_zero() -> None:
+    with mocked_time() as mock_time:
+        # The construction of the timer doesn't throw, yet
+        exponentialBackoff = ExponentialBackoffTimer(timeout=0)
+        # But the first `sleep` immediately throws
+        with pytest.raises(TimeoutError):
             exponentialBackoff.sleep()
-            self.assertAlmostEqual(mock_time(), 4.5)
-            # The next call to `sleep` will raise a TimeoutError
-            with self.assertRaises(TimeoutError):
-                exponentialBackoff.sleep()
-
-    def test_timeout_zero(self):
-        with mocked_time() as mock_time:
-            # The construction of the timer doesn't throw, yet
-            exponentialBackoff = ExponentialBackoffTimer(timeout=0)
-            # But the first `sleep` immediately throws
-            with self.assertRaises(TimeoutError):
-                exponentialBackoff.sleep()