Correct testbed icon tests, and add explicit platform icon test.

android/tests_backend/icons.py

@@ -1,6 +1,10 @@
+from pathlib import Path
+
 import pytest
 from android.graphics import Bitmap
 
+import toga_android
+
 from .probe import BaseProbe
 
 
@@ -26,4 +30,10 @@ def assert_icon_content(self, path):
             pytest.fail("Unknown icon resource")
 
     def assert_default_icon_content(self):
-        assert self.icon._impl.path == self.app.paths.toga / "resources/toga.png"
+        assert (
+            self.icon._impl.path
+            == Path(toga_android.__file__).parent / "resources/toga.png"
+        )
+
+    def assert_platform_icon_content(self):
+        assert self.icon._impl.path == self.app.paths.app / "resources/logo-android.png"

cocoa/tests_backend/icons.py

@@ -1,5 +1,8 @@
+from pathlib import Path
+
 import pytest
 
+import toga_cocoa
 from toga_cocoa.libs import NSImage
 
 from .probe import BaseProbe
@@ -28,4 +31,10 @@ def assert_icon_content(self, path):
             pytest.fail("Unknown icon resource")
 
     def assert_default_icon_content(self):
-        assert self.icon._impl.path == self.app.paths.toga / "resources/toga.icns"
+        assert (
+            self.icon._impl.path
+            == Path(toga_cocoa.__file__).parent / "resources/toga.icns"
+        )
+
+    def assert_platform_icon_content(self):
+        assert self.icon._impl.path == self.app.paths.app / "resources/logo-macOS.icns"

gtk/tests_backend/icons.py

@@ -1,5 +1,8 @@
+from pathlib import Path
+
 import pytest
 
+import toga_gtk
 from toga_gtk.libs import GdkPixbuf
 
 from .probe import BaseProbe
@@ -34,7 +37,14 @@ def assert_icon_content(self, path):
 
     def assert_default_icon_content(self):
         assert self.icon._impl.paths == {
-            16: self.app.paths.toga / "resources/toga.png",
-            32: self.app.paths.toga / "resources/toga.png",
-            72: self.app.paths.toga / "resources/toga.png",
+            16: Path(toga_gtk.__file__).parent / "resources/toga.png",
+            32: Path(toga_gtk.__file__).parent / "resources/toga.png",
+            72: Path(toga_gtk.__file__).parent / "resources/toga.png",
+        }
+
+    def assert_platform_icon_content(self):
+        assert self.icon._impl.paths == {
+            16: self.app.paths.app / "resources/logo-linux-16.png",
+            32: self.app.paths.app / "resources/logo-linux-32.png",
+            72: self.app.paths.app / "resources/logo-linux-72.png",
         }

iOS/tests_backend/icons.py

@@ -1,5 +1,8 @@
+from pathlib import Path
+
 import pytest
 
+import toga_iOS
 from toga_iOS.libs import UIImage
 
 from .probe import BaseProbe
@@ -28,4 +31,10 @@ def assert_icon_content(self, path):
             pytest.fail("Unknown icon resource")
 
     def assert_default_icon_content(self):
-        assert self.icon._impl.path == self.app.paths.toga / "resources/toga.icns"
+        assert (
+            self.icon._impl.path
+            == Path(toga_iOS.__file__).parent / "resources/toga.icns"
+        )
+
+    def assert_platform_icon_content(self):
+        assert self.icon._impl.path == self.app.paths.app / "resources/logo-iOS.icns"

testbed/tests/test_icons.py

@@ -31,6 +31,12 @@ async def test_system_icon(app):
     probe.assert_default_icon_content()
 
 
+async def test_platform_icon(app):
+    "A platform-specific icon can be loaded"
+    probe = icon_probe(app, toga.Icon("resources/logo"))
+    probe.assert_platform_icon_content()
+
+
 async def test_bad_icon_file(app):
     "If a file isn't a loadable icon, an error is raised"
     with pytest.raises(

winforms/tests_backend/icons.py

@@ -1,6 +1,10 @@
+from pathlib import Path
+
 import pytest
 from System.Drawing import Icon as WinIcon
 
+import toga_winforms
+
 from .probe import BaseProbe
 
 
@@ -26,4 +30,12 @@ def assert_icon_content(self, path):
             pytest.fail("Unknown icon resource")
 
     def assert_default_icon_content(self):
-        assert self.icon._impl.path == self.app.paths.toga / "resources/toga.ico"
+        assert (
+            self.icon._impl.path
+            == Path(toga_winforms.__file__).parent / "resources/toga.ico"
+        )
+
+    def assert_platform_icon_content(self):
+        assert (
+            self.icon._impl.path == self.app.paths.app / "resources/logo-winforms.ico"
+        )