Only use resize signal if supported

enlighten.py

@@ -34,6 +34,8 @@
 
 SERIES_STD = u' ▏▎▍▌▋▊▉█'
 
+RESIZE_SUPPORTED = hasattr(signal, 'SIGWINCH')
+
 __version__ = '1.0.6'
 
 
@@ -548,7 +550,8 @@ def __init__(self, stream=None, counter_class=Counter, **kwargs):
         self.width = self.term.width
         self.set_scroll = kwargs.pop('set_scroll', True)
         self.resize_lock = False
-        self.sigwinch_orig = signal.getsignal(signal.SIGWINCH)
+        if RESIZE_SUPPORTED:
+            self.sigwinch_orig = signal.getsignal(signal.SIGWINCH)
 
         self.defaults = kwargs  # Counter defaults
 
@@ -668,7 +671,8 @@ def _set_scroll_area(self, force=False):
         # Set exit handling only once
         if not self.process_exit:
             atexit.register(self._at_exit)
-            signal.signal(signal.SIGWINCH, self._resize_handler)
+            if RESIZE_SUPPORTED:
+                signal.signal(signal.SIGWINCH, self._resize_handler)
             self.process_exit = True
 
         if self.set_scroll:
@@ -752,7 +756,8 @@ def stop(self):
             stream = self.stream
             positions = self.counters.values()
 
-            signal.signal(signal.SIGWINCH, self.sigwinch_orig)
+            if RESIZE_SUPPORTED:
+                signal.signal(signal.SIGWINCH, self.sigwinch_orig)
 
             try:
                 for num in range(self.scroll_offset - 1, 0, -1):

tests/test_enlighten.py

@@ -1133,6 +1133,54 @@ def test_context_manager(self):
 
         self.assertFalse(mgr.enabled)
 
+    def test_no_resize_signal(self):
+
+        # Test normal case initialization
+        stdmgr = enlighten.Manager(stream=self.tty.stdout)
+        self.assertTrue(hasattr(stdmgr, 'sigwinch_orig'))
+        stdmgr.counters[MockCounter(manager=stdmgr)] = 3
+        stdmgr.counters[MockCounter(manager=stdmgr)] = 4
+
+        # Test no resize signal initialization
+        with mock.patch.object(enlighten, 'RESIZE_SUPPORTED', False):
+            manager = enlighten.Manager(stream=self.tty.stdout)
+            self.assertFalse(hasattr(manager, 'sigwinch_orig'))
+
+            manager.counters[MockCounter(manager=manager)] = 3
+            manager.counters[MockCounter(manager=manager)] = 4
+
+        # Test set_scroll_area()
+        with mock.patch.object(enlighten.signal, 'signal',
+                               wraps=enlighten.signal.signal) as mocksignal:
+            with mock.patch('enlighten.atexit'):
+
+                # Test no resize signal set_scroll_area
+                with mock.patch.object(enlighten, 'RESIZE_SUPPORTED', False):
+                    with mock.patch.object(manager.term, 'change_scroll'):
+                        manager._set_scroll_area()
+
+                self.assertFalse(mocksignal.called)
+
+                # Test normal case set_scroll_area
+                with mock.patch.object(stdmgr.term, 'change_scroll'):
+                    stdmgr._set_scroll_area()
+                self.assertTrue(mocksignal.called)
+
+        # Test stop()
+        with mock.patch.object(enlighten.signal, 'signal',
+                               wraps=enlighten.signal.signal) as mocksignal:
+
+            with mock.patch('enlighten.Terminal.reset'):
+
+                # Test no resize signal stop
+                with mock.patch.object(enlighten, 'RESIZE_SUPPORTED', False):
+                    manager.stop()
+                self.assertFalse(mocksignal.called)
+
+                # Test normal case stop
+                stdmgr.stop()
+                self.assertTrue(mocksignal.called)
+
 
 class TestGetManager(TestCase):