Rollup merge of #93453 - GuillaumeGomez:theme-change-test, r=jsha

Add GUI theme change test

r? `@jsha`

Author: matthiaskrgr

src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile

@@ -72,7 +72,7 @@ ENV PATH="/node-v14.4.0-linux-x64/bin:${PATH}"
 # https://github.com/puppeteer/puppeteer/issues/375
 #
 # We also specify the version in case we need to update it to go around cache limitations.
-RUN npm install -g browser-ui-test@0.5.3 --unsafe-perm=true
+RUN npm install -g browser-ui-test@0.5.8 --unsafe-perm=true
 
 ENV RUST_CONFIGURE_ARGS \
   --build=x86_64-unknown-linux-gnu \

src/test/rustdoc-gui/theme-change.goml

@@ -9,3 +9,19 @@ click: "#theme-choices > button:last-child"
 wait-for: 500
 // should be the light theme so let's check the color
 assert-css: ("body", { "background-color": "rgb(255, 255, 255)" })
+
+goto: file://|DOC_PATH|/settings.html
+click: "#theme-light"
+wait-for: 500
+assert-css: ("body", { "background-color": "rgb(255, 255, 255)" })
+assert-local-storage: { "rustdoc-theme": "light" }
+
+click: "#theme-dark"
+wait-for: 500
+assert-css: ("body", { "background-color": "rgb(53, 53, 53)" })
+assert-local-storage: { "rustdoc-theme": "dark" }
+
+click: "#theme-ayu"
+wait-for: 500
+assert-css: ("body", { "background-color": "rgb(15, 20, 25)" })
+assert-local-storage: { "rustdoc-theme": "ayu" }