Extend GUI test for run button

src/test/rustdoc-gui/run-on-hover.goml

@@ -1,7 +1,54 @@
 // Example code blocks sometimes have a "Run" button to run them on the
 // Playground. That button is hidden until the user hovers over the code block.
-// This test checks that it is hidden, and that it shows on hover.
+// This test checks that it is hidden, and that it shows on hover. It also
+// checks for its color.
 goto: "file://" + |DOC_PATH| + "/test_docs/fn.foo.html"
-assert-css: (".test-arrow", {"visibility": "hidden"})
-move-cursor-to: ".example-wrap"
-assert-css: (".test-arrow", {"visibility": "visible"})
+show-text: true
+
+define-function: (
+    "check-run-button",
+    (theme, color, background, hover_color, hover_background),
+    [
+        ("local-storage", {"rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false"}),
+        ("reload"),
+        ("assert-css", (".test-arrow", {"visibility": "hidden"})),
+        ("move-cursor-to", ".example-wrap"),
+        ("assert-css", (".test-arrow", {
+            "visibility": "visible",
+            "color": |color|,
+            "background-color": |background|,
+            "font-size": "22px",
+            "border-radius": "5px",
+        })),
+        ("move-cursor-to", ".test-arrow"),
+        ("assert-css", (".test-arrow:hover", {
+            "visibility": "visible",
+            "color": |hover_color|,
+            "background-color": |hover_background|,
+            "font-size": "22px",
+            "border-radius": "5px",
+        })),
+    ],
+)
+
+call-function: ("check-run-button", {
+    "theme": "ayu",
+    "color": "rgb(120, 135, 151)",
+    "background": "rgba(57, 175, 215, 0.09)",
+    "hover_color": "rgb(197, 197, 197)",
+    "hover_background": "rgba(57, 175, 215, 0.37)",
+})
+call-function: ("check-run-button", {
+    "theme": "dark",
+    "color": "rgb(222, 222, 222)",
+    "background": "rgba(78, 139, 202, 0.2)",
+    "hover_color": "rgb(222, 222, 222)",
+    "hover_background": "rgb(78, 139, 202)",
+})
+call-function: ("check-run-button", {
+    "theme": "light",
+    "color": "rgb(245, 245, 245)",
+    "background": "rgba(78, 139, 202, 0.2)",
+    "hover_color": "rgb(245, 245, 245)",
+    "hover_background": "rgb(78, 139, 202)",
+})