Fix testbed coverage for Wayland on Linux

gtk/src/toga_gtk/app.py

@@ -192,13 +192,13 @@ def set_main_window(self, window):
 
     def get_screens(self):
         display = Gdk.Display.get_default()
-        if "WAYLAND_DISPLAY" in os.environ:  # pragma: no cover
+        if "WAYLAND_DISPLAY" in os.environ:  # pragma: no-cover-if-linux-x
             # `get_primary_monitor()` doesn't work on wayland, so return as it is.
             return [
                 ScreenImpl(native=display.get_monitor(i))
                 for i in range(display.get_n_monitors())
             ]
-        else:
+        else:  # pragma: no-cover-if-linux-wayland
             primary_screen = ScreenImpl(display.get_primary_monitor())
             screen_list = [primary_screen] + [
                 ScreenImpl(native=display.get_monitor(i))
@@ -252,7 +252,7 @@ def show_cursor(self):
     # Window control
     ######################################################################
 
-    def get_current_window(self):
+    def get_current_window(self):  # pragma: no-cover-if-linux-wayland
         current_window = self.native.get_active_window()._impl
         return current_window if current_window.interface.visible else None
 

gtk/src/toga_gtk/screens.py

@@ -31,10 +31,10 @@ def get_size(self) -> Size:
         return Size(geometry.width, geometry.height)
 
     def get_image_data(self):
-        if "WAYLAND_DISPLAY" in os.environ:
+        if "WAYLAND_DISPLAY" in os.environ:  # pragma: no-cover-if-linux-x
             # Not implemented on wayland due to wayland security policies.
             self.interface.factory.not_implemented("Screen.get_image_data() on Wayland")
-        else:
+        else:  # pragma: no-cover-if-linux-wayland
             # Only works for Xorg
             display = self.native.get_display()
             screen = display.get_default_screen()

testbed/pyproject.toml

@@ -5,6 +5,7 @@ version = "0.0.1"
 [project.optional-dependencies]
 test = [
     "coverage==7.5.3",
+    "coverage-conditional-plugin == 0.9.0",
     # fonttools is only needed by Android, but we need to use
     # sys.platform == 'linux' as there's no dependency identifier
     # that can target Android exclusively until 3.13 lands.

testbed/tests/testbed.py

@@ -115,6 +115,14 @@ def run_tests(app, cov, args, report_coverage, run_slow):
         branch=True,
         source_pkgs=[toga_backend],
     )
+    cov.set_option("run:plugins", ["coverage_conditional_plugin"])
+    cov.set_option(
+        "coverage_conditional_plugin:rules",
+        {
+            "no-cover-if-linux-wayland": "os_environ.get('WAYLAND_DISPLAY') != ''",
+            "no-cover-if-linux-x": "os_environ.get('WAYLAND_DISPLAY', 'not-set') == 'not-set'",
+        },
+    )
     cov.start()
 
     # Create the test app, starting the test suite as a background task