Move playwrite stuff to utils folder

e2e/utils/fixtures.ts

@@ -0,0 +1,81 @@
+import { test, expect, type Page } from "@playwright/test";
+import fs from "node:fs";
+import path from "node:path";
+
+let activePage: Page | undefined;
+const coverageChunks: unknown[] = [];
+
+/** The page for the currently running test. Throws if used outside a test. */
+export function currentPage(): Page {
+  if (!activePage) {
+    throw new Error("No active page: a MaputnikDriver method was called outside of a running test.");
+  }
+  return activePage;
+}
+
+const OUTPUT_DIR = path.resolve(process.cwd(), ".nyc_output");
+
+/**
+ * Reads the istanbul coverage object (injected by vite-plugin-istanbul) from the
+ * given page. Returns `null` when the page has not been instrumented.
+ */
+export async function readCoverage(page: Page): Promise<unknown | null> {
+  try {
+    return await page.evaluate(() => (window as unknown as { __coverage__?: unknown }).__coverage__ ?? null);
+  } catch {
+    // Page might be navigating/closed.
+    return null;
+  }
+}
+
+/**
+ * Persists a coverage chunk to `.nyc_output` so that `nyc report` can merge it.
+ * istanbul-lib-coverage (used by nyc) sums the hit counts across every file it
+ * finds, so writing one file per chunk is enough to accumulate coverage across
+ * navigations and tests.
+ */
+export function writeCoverage(coverage: unknown, id: string): void {
+  if (!coverage) return;
+  fs.mkdirSync(OUTPUT_DIR, { recursive: true });
+  fs.writeFileSync(path.join(OUTPUT_DIR, `playwright-${id}.json`), JSON.stringify(coverage));
+}
+
+/** Records a coverage snapshot (called before navigations, which reset __coverage__). */
+export function recordCoverageChunk(chunk: unknown): void {
+  if (chunk) coverageChunks.push(chunk);
+}
+
+/**
+ * Auto fixture that binds the current test's page for the (page-lazy)
+ * MaputnikDriver, auto-accepts confirm dialogs, and writes the istanbul
+ * coverage collected during the test to `.nyc_output`.
+ */
+const extendedTest = test.extend<{ maputnikPage: void }>({
+  maputnikPage: [
+    async ({ page }, use, testInfo) => {
+      activePage = page;
+      coverageChunks.length = 0;
+      // Accept confirm dialogs (e.g. the "replace current style" prompt). These
+      // are dismissed by default, which would cancel loading a style via URL.
+      page.on("dialog", (dialog) => dialog.accept().catch(() => undefined));
+
+      await use();
+
+      const finalCoverage = await readCoverage(page);
+      if (finalCoverage) coverageChunks.push(finalCoverage);
+      coverageChunks.forEach((chunk, index) => writeCoverage(chunk, `${testInfo.testId}-${index}`));
+      coverageChunks.length = 0;
+      activePage = undefined;
+    },
+    { auto: true },
+  ],
+});
+
+const describe = extendedTest.describe;
+const beforeEach = extendedTest.beforeEach;
+export {
+  expect,
+  describe,
+  extendedTest as test,
+  beforeEach,
+};