1 files changed, 60 insertions, 0 deletions
diff --git a/devtools/client/responsive/test/browser/browser_viewport_zoom_resolution_invariant.js b/devtools/client/responsive/test/browser/browser_viewport_zoom_resolution_invariant.js
new file mode 100644
index 0000000000..69c6c0a95b
--- /dev/null
+++ b/devtools/client/responsive/test/browser/browser_viewport_zoom_resolution_invariant.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that resolution is as expected for different types of meta viewport
+// settings, as the RDM pane is zoomed to different values.
+
+const RESOLUTION_FACTOR_MIN = 0.96;
+const RESOLUTION_FACTOR_MAX = 1.04;
+const ZOOM_LEVELS = [
+  0.3, 0.5, 0.67, 0.8, 0.9, 1.0, 1.1, 1.2, 1.33, 1.5, 1.7, 2.0, 2.4, 3.0,
+  // TODO(emilio): These should pass.
+  // 0.3,
+  // 3.0,
+];
+
+info("--- Starting viewport test output ---");
+
+const WIDTH = 200;
+const HEIGHT = 200;
+const TESTS = [
+  { content: "width=600", res_target: 0.333 },
+  { content: "width=600, initial-scale=1.0", res_target: 1.0 },
+  { content: "width=device-width", res_target: 1.0 },
+  { content: "width=device-width, initial-scale=2.0", res_target: 2.0 },
+];
+
+for (const { content, res_target } of TESTS) {
+  const TEST_URL =
+    `data:text/html;charset=utf-8,` +
+    `<html><head><meta name="viewport" content="${content}"></head>` +
+    `<body><div style="width:100%;background-color:green">${content}</div>` +
+    `</body></html>`;
+
+  addRDMTask(TEST_URL, async function ({ ui, manager, browser }) {
+    await setViewportSize(ui, manager, WIDTH, HEIGHT);
+    await setTouchAndMetaViewportSupport(ui, true);
+
+    // Ensure we've reflowed the page at least once so that MVM has chosen
+    // the initial scale.
+    await promiseContentReflow(ui);
+
+    for (const zoom of ZOOM_LEVELS.concat([...ZOOM_LEVELS].reverse())) {
+      info(`Set zoom to ${zoom}.`);
+      await promiseRDMZoom(ui, browser, zoom);
+
+      const resolution = await spawnViewportTask(ui, {}, () => {
+        return content.windowUtils.getResolution();
+      });
+
+      const res_min = res_target * RESOLUTION_FACTOR_MIN;
+      const res_max = res_target * RESOLUTION_FACTOR_MAX;
+      ok(
+        res_min <= resolution && res_max >= resolution,
+        `${content} zoom ${zoom} resolution should be near ${res_target}, and we got ${resolution}.`
+      );
+    }
+  });
+}