Use monotonic time and the configured interval for spinner pacing

humanfriendly/terminal/spinners.py

@@ -98,6 +98,7 @@
 
 # Modules included in our package.
 from humanfriendly import Timer
+from humanfriendly.compat import monotonic
 from humanfriendly.deprecation import deprecated_args
 from humanfriendly.terminal import ANSI_ERASE_LINE
 
@@ -166,7 +167,7 @@ def __init__(self, **options):
         self.total = options.get('total')
         # Define instance variables.
         self.counter = 0
-        self.last_update = 0
+        self.last_update = None
         # Try to automatically discover whether the stream is connected to
         # a terminal, but don't fail if no isatty() method is available.
         if self.interactive is None:
@@ -199,8 +200,8 @@ def step(self, progress=0, label=None):
                   99% of the time.
         """
         if self.interactive:
-            time_now = time.time()
-            if time_now - self.last_update >= self.interval:
+            time_now = monotonic()
+            if self.last_update is None or time_now - self.last_update >= self.interval:
                 self.last_update = time_now
                 state = self.states[self.counter % len(self.states)]
                 label = label or self.label
@@ -226,7 +227,7 @@ def sleep(self):
         This method doesn't redraw the spinner, you still have to call
         :func:`step()` in order to do that.
         """
-        time.sleep(MINIMUM_INTERVAL)
+        time.sleep(self.interval)
 
     def clear(self):
         """

humanfriendly/tests.py

@@ -797,6 +797,31 @@ def test_spinner(self):
         self.assertTrue(all('%' in line for line in lines))
         self.assertEqual(sorted(set(lines)), sorted(lines))
 
+    def test_spinner_uses_elapsed_time(self):
+        """Keep redrawing after a wall-clock correction and at clock zero."""
+        from humanfriendly.terminal import spinners
+        stream = StringIO()
+        clock = [0.0]
+        with PatchedAttribute(spinners, 'monotonic', lambda: clock[0]):
+            with PatchedAttribute(spinners.time, 'time', lambda: 1000 - clock[0]):
+                spinner = Spinner(label='working', stream=stream, interactive=True, interval=1)
+                spinner.step()
+                assert spinner.counter == 1
+                clock[0] = 0.5
+                spinner.step()
+                assert spinner.counter == 1
+                clock[0] = 1.0
+                spinner.step()
+                assert spinner.counter == 2
+
+    def test_spinner_sleep_uses_configured_interval(self):
+        """Sleep for the interval chosen for the spinner's redraw cadence."""
+        from humanfriendly.terminal import spinners
+        sleep = MagicMock()
+        with PatchedAttribute(spinners.time, 'sleep', sleep):
+            Spinner(interval=0.7).sleep()
+        sleep.assert_called_once_with(0.7)
+
     def test_automatic_spinner(self):
         """
         Test :func:`humanfriendly.AutomaticSpinner`.