Add test for screen shot part

Author: Mickaël Schoentgen

mss/darwin.py

@@ -49,14 +49,14 @@ class CGRect(Structure):
 
 
 class MSS(MSSBase):
-    ''' Mutliple ScreenShots implementation for MacOS X.
+    ''' Mutliple ScreenShots implementation for macOS.
         It uses intensively the Quartz.
     '''
 
     max_displays = 32  # Could be augmented, if needed ...
 
     def __init__(self):
-        ''' MacOS X initialisations. '''
+        ''' macOS initialisations. '''
 
         coregraphics = find_library('CoreGraphics')
         if not coregraphics:

tests/test_attributes.py

@@ -2,17 +2,8 @@
 # coding: utf-8
 
 
-def test_attribute_image(sct):
+def test_attributes(sct):
     assert sct.image is None
-
-
-def test_attribute_monitors(sct):
     assert sct.monitors == []
-
-
-def test_attribute_width(sct):
     assert sct.width == 0
-
-
-def test_attribute_height(sct):
     assert sct.height == 0

tests/test_get_pixels.py

@@ -7,3 +7,12 @@ def test_get_pixels(sct):
     pixels = sct.get_pixels(mon1)
     assert pixels is sct.image
     assert isinstance(sct.image, bytes)
+
+
+def test_get_pixels_part_of_screen(sct):
+    mon = {'top': 160, 'left': 160, 'width': 222, 'height': 42}
+    pixels = sct.get_pixels(mon)
+    assert pixels is sct.image
+    assert isinstance(sct.image, bytes)
+    assert sct.width == 222
+    assert sct.height == 42