gui tests: signin-paste-codex, signin-again and signin-closes-sheet give the sign-in window they open an empty page instead of the real vendor's (#1307's siblings)

Found by logging every off-host request in a full Chromium GUI run:
signin-paste-codex opened the real auth.openai.com (Cloudflare's
challenge, the page that hung login-import's clicks), signin-again
loaded www.codebuddy.cn with its downloads and trackers, and
signin-closes-sheet example.com. Each routed only its page. Now the
context answers anything off magpie.test with an empty page; a rerun
logged only the three window URLs, no subresources. Chromium and
WebKit, all three files: 9/9 pass each.

internal/gui/tests/signin-again.test.cjs

@@ -68,6 +68,10 @@ for (const engine of (process.env.BROWSER ? [process.env.BROWSER] : ["chromium",
         const errors = [];
         page.on("pageerror", (e) => errors.push(e.message));
         await page.route("**/*", serve(lang, [c.done]));
+        // the vendor's sign-in page, opened in a new window, gets an empty page:
+        // the real one is a page the test can't control (ChatGPT's Cloudflare
+        // challenge hung clicks on this page in Chromium, #1307)
+        await page.context().route((url) => url.hostname !== "magpie.test", (route) => route.fulfill({ contentType: "text/html", body: "" }));
         await page.goto("http://magpie.test/?view=providers");
         await page.locator(".row.provider", { hasText: "WorkBuddy" }).click();
         const add = page.locator(".editor .accts .acc.add").first();

internal/gui/tests/signin-closes-sheet.test.cjs

@@ -62,6 +62,10 @@ for (const engine of (process.env.BROWSER ? [process.env.BROWSER] : ["chromium",
         page.setDefaultTimeout(5000);
         page.on("pageerror", (e) => errors.push(e.message));
         await page.route("**/*", serve(lang));
+        // the vendor's sign-in page, opened in a new window, gets an empty page:
+        // the real one is a page the test can't control (ChatGPT's Cloudflare
+        // challenge hung clicks on this page in Chromium, #1307)
+        await page.context().route((url) => url.hostname !== "magpie.test", (route) => route.fulfill({ contentType: "text/html", body: "" }));
         await page.goto("http://magpie.test/?view=providers");
         await page.locator("#providers .row").nth(9).waitFor();
         await page.locator("#addProvider").click();

internal/gui/tests/signin-paste-codex.test.cjs

@@ -70,6 +70,10 @@ for (const engine of (process.env.BROWSER ? [process.env.BROWSER] : ["chromium",
       const errors = [], posted = [];
       page.on("pageerror", (e) => errors.push(e.message));
       await page.route("**/*", server(lang, posted));
+      // the vendor's sign-in page, opened in a new window, gets an empty page:
+      // the real one is a page the test can't control (ChatGPT's Cloudflare
+      // challenge hung clicks on this page in Chromium, #1307)
+      await page.context().route((url) => url.hostname !== "magpie.test", (route) => route.fulfill({ contentType: "text/html", body: "" }));
       await page.goto("http://magpie.test/?view=providers");
       await page.locator("#addProvider").click();
       const sheet = page.locator("#addSheet");