Fix the "Signature Editor Basic operations must check copy and paste" integration test

This integration test fails intermittently because of concurrent
clipboard access due to running the test in parallel in both browsers.
It can be reproduced by introducing `await waitForTimeout(1000)` between
the copy and paste operations.

This commit fixes the issue by running the test sequentially instead,
mirroring the change from commit 0e94f2b.

Author: timvandermeij

test/integration/signature_editor_spec.mjs

@@ -339,45 +339,44 @@ describe("Signature Editor", () => {
     });
 
     it("must check copy and paste", async () => {
-      await Promise.all(
-        pages.map(async ([browserName, page]) => {
-          await switchToSignature(page);
-          await page.click("#editorSignatureAddSignature");
-
-          await page.waitForSelector("#addSignatureDialog", {
-            visible: true,
-          });
-          await page.type("#addSignatureTypeInput", "Hello");
-          await page.waitForSelector(`${addButtonSelector}:not(:disabled)`);
-          await page.click("#addSignatureAddButton");
-
-          const editorSelector = getEditorSelector(0);
-          await page.waitForSelector(editorSelector, { visible: true });
-          const originalRect = await getRect(page, editorSelector);
-          const originalDescription = await page.$eval(
-            `${editorSelector} .altText.editDescription`,
-            el => el.title
-          );
-
-          await copy(page);
-          await paste(page);
-
-          const pastedEditorSelector = getEditorSelector(1);
-          await page.waitForSelector(pastedEditorSelector, { visible: true });
-          const pastedRect = await getRect(page, pastedEditorSelector);
-          const pastedDescription = await page.$eval(
-            `${pastedEditorSelector} .altText.editDescription`,
-            el => el.title
-          );
-
-          expect(pastedRect)
-            .withContext(`In ${browserName}`)
-            .not.toEqual(originalRect);
-          expect(pastedDescription)
-            .withContext(`In ${browserName}`)
-            .toEqual(originalDescription);
-        })
-      );
+      // Run sequentially to avoid clipboard issues.
+      for (const [browserName, page] of pages) {
+        await switchToSignature(page);
+        await page.click("#editorSignatureAddSignature");
+
+        await page.waitForSelector("#addSignatureDialog", {
+          visible: true,
+        });
+        await page.type("#addSignatureTypeInput", "Hello");
+        await page.waitForSelector(`${addButtonSelector}:not(:disabled)`);
+        await page.click("#addSignatureAddButton");
+
+        const editorSelector = getEditorSelector(0);
+        await page.waitForSelector(editorSelector, { visible: true });
+        const originalRect = await getRect(page, editorSelector);
+        const originalDescription = await page.$eval(
+          `${editorSelector} .altText.editDescription`,
+          el => el.title
+        );
+
+        await copy(page);
+        await paste(page);
+
+        const pastedEditorSelector = getEditorSelector(1);
+        await page.waitForSelector(pastedEditorSelector, { visible: true });
+        const pastedRect = await getRect(page, pastedEditorSelector);
+        const pastedDescription = await page.$eval(
+          `${pastedEditorSelector} .altText.editDescription`,
+          el => el.title
+        );
+
+        expect(pastedRect)
+          .withContext(`In ${browserName}`)
+          .not.toEqual(originalRect);
+        expect(pastedDescription)
+          .withContext(`In ${browserName}`)
+          .toEqual(originalDescription);
+      }
     });
   });