tests: fix tests on macOS with Retina display

Author: Mickaël Schoentgen

CHANGELOG

@@ -5,6 +5,7 @@ History:
 5.0.1   2020/xx/xx
       - produce wheels for Python 3 only
       - tools: force write of file when saving a PNG file
+      - tests: fix tests on macOS with Retina display
 
 5.0.0   2019/12/31
       - removed support for Python 2.7

mss/tests/conftest.py

@@ -6,8 +6,8 @@
 import glob
 import os
 
-import mss
 import pytest
+import mss
 
 
 def purge_files():
@@ -47,3 +47,15 @@ def raw():
     file = os.path.join(here, "res", "monitor-1024x768.raw")
     with open(file, "rb") as f:
         yield f.read()
+
+
+@pytest.fixture(scope="module")
+def pixel_ratio(sct):
+    """Get the pixel, used to adapt test checks."""
+    # Grab a 1x1 screenshot
+    region = {"top": 0, "left": 0, "width": 1, "height": 1}
+
+    # On macOS with Retina display,the width will be 2 instead of 1
+    pixel_size = sct.grab(region).size[0]
+
+    return pixel_size

mss/tests/test_get_pixels.py

@@ -16,28 +16,28 @@ def test_grab_monitor(sct):
         assert isinstance(image.rgb, bytes)
 
 
-def test_grab_part_of_screen(sct):
+def test_grab_part_of_screen(sct, pixel_ratio):
     monitor = {"top": 160, "left": 160, "width": 160, "height": 160}
     image = sct.grab(monitor)
     assert isinstance(image, ScreenShot)
     assert isinstance(image.raw, bytearray)
     assert isinstance(image.rgb, bytes)
     assert image.top == 160
     assert image.left == 160
-    assert image.width == 160
-    assert image.height == 160
+    assert image.width == 160 * pixel_ratio
+    assert image.height == 160 * pixel_ratio
 
 
-def test_grab_part_of_screen_rounded(sct):
+def test_grab_part_of_screen_rounded(sct, pixel_ratio):
     monitor = {"top": 160, "left": 160, "width": 161, "height": 159}
     image = sct.grab(monitor)
     assert isinstance(image, ScreenShot)
     assert isinstance(image.raw, bytearray)
     assert isinstance(image.rgb, bytes)
     assert image.top == 160
     assert image.left == 160
-    assert image.width == 161
-    assert image.height == 159
+    assert image.width == 161 * pixel_ratio
+    assert image.height == 159 * pixel_ratio
 
 
 def test_grab_individual_pixels(sct):

mss/tests/test_implementation.py

@@ -63,10 +63,16 @@ def test_incomplete_class():
         sct.grab(sct.shot(mon=222))
 
 
-def test_repr(sct):
+def test_repr(sct, pixel_ratio):
     box = {"top": 0, "left": 0, "width": 10, "height": 10}
+    expected_box = {
+        "top": 0,
+        "left": 0,
+        "width": 10 * pixel_ratio,
+        "height": 10 * pixel_ratio,
+    }
     img = sct.grab(box)
-    ref = ScreenShot(bytearray(b"42"), box)
+    ref = ScreenShot(bytearray(b"42"), expected_box)
     assert repr(img) == repr(ref)
 
 
@@ -140,7 +146,7 @@ def test_entry_point(capsys, sct):
         assert out == "Coordinates syntax: top, left, width, height\n"
 
 
-def test_grab_with_tuple(sct):
+def test_grab_with_tuple(sct, pixel_ratio):
     left = 100
     top = 100
     right = 500
@@ -151,7 +157,7 @@ def test_grab_with_tuple(sct):
     # PIL like
     box = (left, top, right, lower)
     im = sct.grab(box)
-    assert im.size == (width, height)
+    assert im.size == (width * pixel_ratio, height * pixel_ratio)
 
     # MSS like
     box2 = {"left": left, "top": top, "width": width, "height": height}
@@ -161,7 +167,7 @@ def test_grab_with_tuple(sct):
     assert im.rgb == im2.rgb
 
 
-def test_grab_with_tuple_percents(sct):
+def test_grab_with_tuple_percents(sct, pixel_ratio):
     monitor = sct.monitors[1]
     left = monitor["left"] + monitor["width"] * 5 // 100  # 5% from the left
     top = monitor["top"] + monitor["height"] * 5 // 100  # 5% from the top
@@ -173,7 +179,7 @@ def test_grab_with_tuple_percents(sct):
     # PIL like
     box = (left, top, right, lower)
     im = sct.grab(box)
-    assert im.size == (width, height)
+    assert im.size == (width * pixel_ratio, height * pixel_ratio)
 
     # MSS like
     box2 = {"left": left, "top": top, "width": width, "height": height}

mss/tests/test_third_party.py

@@ -21,10 +21,10 @@
 
 
 @pytest.mark.skipif(numpy is None, reason="Numpy module not available.")
-def test_numpy(sct):
+def test_numpy(sct, pixel_ratio):
     box = {"top": 0, "left": 0, "width": 10, "height": 10}
     img = numpy.array(sct.grab(box))
-    assert len(img) == 10
+    assert len(img) == 10 * pixel_ratio
 
 
 @pytest.mark.skipif(Image is None, reason="PIL module not available.")