Yet another fix of Screen.set_margins

for the case of CSI with no arguments. See #61.

CHANGES

@@ -6,6 +6,10 @@ Here you can see the full list of changes between each pyte release.
 Version 0.8.1-dev
 -----------------
 
+- Yet another fix of ``Screen.set_margins`` for the case of CSI
+  with no arguments. See issue #61 on GitHub.
+
+
 Version 0.8.0
 -------------
 

pyte/screens.py

@@ -331,7 +331,8 @@ def set_margins(self, top=None, bottom=None):
         :param int top: the smallest line number that is scrolled.
         :param int bottom: the biggest line number that is scrolled.
         """
-        if top is None and bottom is None:
+        # XXX 0 corresponds to the CSI with no parameters.
+        if (top is None or top == 0) and bottom is None:
             self.margins = None
             return
 

tests/test_screen.py

@@ -1457,6 +1457,15 @@ def test_set_margins():
     assert screen.margins is None
 
 
+def test_set_margins_zero():
+    # See https://github.com/selectel/pyte/issues/61
+    screen = pyte.Screen(80, 24)
+    screen.set_margins(1, 5)
+    assert screen.margins == (0, 4)
+    screen.set_margins(0)
+    assert screen.margins is None
+
+
 def test_hide_cursor():
     screen = pyte.Screen(10, 10)