1 files changed, 60 insertions, 0 deletions
diff --git a/devtools/client/responsive/test/browser/browser_viewport_resolution_restore.js b/devtools/client/responsive/test/browser/browser_viewport_resolution_restore.js
new file mode 100644
index 0000000000..6e5f10dff6
--- /dev/null
+++ b/devtools/client/responsive/test/browser/browser_viewport_resolution_restore.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 restored to its pre-RDM value after closing RDM.
+// Do this by using a chrome-only method to force resolution before opening
+// RDM, then letting RDM set its own preferred resolution due to the meta
+// viewport settings. When we close RDM and check resolution, we check for
+// something close to what we initially set, bracketed by these scaling
+// factors:
+const RESOLUTION_FACTOR_MIN = 0.96;
+const RESOLUTION_FACTOR_MAX = 1.04;
+
+info("--- Starting viewport test output ---");
+
+const WIDTH = 200;
+const HEIGHT = 200;
+const TESTS = [
+  { content: "width=600" },
+  { content: "width=600, initial-scale=1.0", res_restore: 0.782 },
+  { content: "width=device-width", res_restore: 3.4 },
+  { content: "width=device-width, initial-scale=2.0", res_restore: 1.1 },
+];
+
+for (const { content, res_restore } 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>`;
+
+  addRDMTaskWithPreAndPost(
+    TEST_URL,
+    async function rdmPreTask({ browser }) {
+      if (res_restore) {
+        info(`Setting resolution to ${res_restore}.`);
+        browser.ownerGlobal.windowUtils.setResolutionAndScaleTo(res_restore);
+      } else {
+        info(`Not setting resolution.`);
+      }
+    },
+    async function rdmTask({ ui, manager }) {
+      info(`Resizing viewport and ensuring that meta viewport is on.`);
+      await setViewportSize(ui, manager, WIDTH, HEIGHT);
+      await setTouchAndMetaViewportSupport(ui, true);
+    },
+    async function rdmPostTask({ browser }) {
+      const resolution = browser.ownerGlobal.windowUtils.getResolution();
+      const res_target = res_restore ? res_restore : 1.0;
+
+      const res_min = res_target * RESOLUTION_FACTOR_MIN;
+      const res_max = res_target * RESOLUTION_FACTOR_MAX;
+      ok(
+        res_min <= resolution && res_max >= resolution,
+        `${content} resolution should be near ${res_target}, and we got ${resolution}.`
+      );
+    }
+  );
+}