1 files changed, 64 insertions, 0 deletions
diff --git a/devtools/client/responsive/test/browser/browser_toolbox_computed_view.js b/devtools/client/responsive/test/browser/browser_toolbox_computed_view.js
new file mode 100644
index 0000000000..f22ee8d246
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+++ b/devtools/client/responsive/test/browser/browser_toolbox_computed_view.js
@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Check that when the viewport is resized, the computed-view refreshes.
+
+const TEST_URI =
+  "data:text/html;charset=utf-8,<html><style>" +
+  "div {" +
+  "  width: 500px;" +
+  "  height: 10px;" +
+  "  background: purple;" +
+  "} " +
+  "@media screen and (max-width: 200px) {" +
+  "  div { " +
+  "    width: 100px;" +
+  "  }" +
+  "};" +
+  "</style><div></div></html>";
+
+addRDMTask(TEST_URI, async function ({ ui, manager }) {
+  info("Open the responsive design mode and set its size to 500x500 to start");
+  await setViewportSize(ui, manager, 500, 500);
+
+  info("Open the inspector, computed-view and select the test node");
+  const { inspector, view } = await openComputedView();
+  await selectNode("div", inspector);
+
+  info("Try shrinking the viewport and checking the applied styles");
+  await testShrink(view, inspector, ui, manager);
+
+  info("Try growing the viewport and checking the applied styles");
+  await testGrow(view, inspector, ui, manager);
+
+  await closeToolbox();
+});
+
+async function testShrink(computedView, inspector, ui, manager) {
+  is(computedWidth(computedView), "500px", "Should show 500px initially.");
+
+  const onRefresh = inspector.once("computed-view-refreshed");
+  await setViewportSize(ui, manager, 100, 100);
+  await onRefresh;
+
+  is(computedWidth(computedView), "100px", "Should be 100px after shrinking.");
+}
+
+async function testGrow(computedView, inspector, ui, manager) {
+  const onRefresh = inspector.once("computed-view-refreshed");
+  await setViewportSize(ui, manager, 500, 500);
+  await onRefresh;
+
+  is(computedWidth(computedView), "500px", "Should be 500px after growing.");
+}
+
+function computedWidth(computedView) {
+  for (const prop of computedView.propertyViews) {
+    if (prop.name === "width") {
+      return prop.valueNode.textContent;
+    }
+  }
+  return null;
+}