Add gui test for scrollbar presence

Author: GuillaumeGomez

gui-tests/no-scrollbar.goml

@@ -0,0 +1,20 @@
+// Checks that there is no x-axis scrollbar.
+
+go-to: |DOC_PATH|
+
+define-function: (
+    "test-scrollbar",
+    [window_width],
+    block {
+        set-window-size: (|window_width|, 1000)
+        store-document-property: {"body"."scrollWidth": scroll_width}
+        // If the scroll width is the same as the viewport width, then all good!
+        assert-document-property: {"documentElement"."clientWidth": |scroll_width|}
+    },
+)
+
+call-function: ("test-scrollbar", {"window_width": 1200})
+call-function: ("test-scrollbar", {"window_width": 1000})
+call-function: ("test-scrollbar", {"window_width": 800})
+call-function: ("test-scrollbar", {"window_width": 600})
+call-function: ("test-scrollbar", {"window_width": 400})