fix(build): test the dry-run header pattern directly

Lift the pattern into dryRunHeaderPattern() so the test exercises it
without a hand-built BuildContext.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Author: NERLOE

packages/build/src/extensions/playwright.test.ts

@@ -1,6 +1,5 @@
 import { describe, expect, it } from "vitest";
-import type { BuildContext, BuildLayer } from "@trigger.dev/core/v3/build";
-import { playwright } from "./playwright.js";
+import { dryRunHeaderPattern } from "./playwright.js";
 
 // Real `playwright install --dry-run` headers, before and after the 1.58 format change.
 const HEADERS = {
@@ -19,52 +18,18 @@ const HEADERS = {
   },
 } as const;
 
-type BrowserKey = keyof (typeof HEADERS)["1.57"];
-
-function generatedInstructions(options: Parameters<typeof playwright>[0]): string[] {
-  let captured: BuildLayer | undefined;
-
-  const context = {
-    target: "deploy",
-    logger: { debug: () => {} },
-    addLayer: (layer: BuildLayer) => {
-      captured = layer;
-    },
-  } as unknown as BuildContext;
-
-  const manifest = {
-    externals: [{ name: "playwright", version: "1.62.0" }],
-  } as any;
-
-  playwright(options).onBuildComplete!(context, manifest);
-
-  return captured?.image?.instructions ?? [];
-}
-
-/** The ERE the generated `grep -E "<pattern>"` step selects a browser's block with. */
-function headerPattern(instructions: string[], browser: BrowserKey): RegExp {
-  const step = instructions.find((line) => line.endsWith(`> /tmp/${browser}-info.txt`));
-  const match = step?.match(/grep [^"]*"(.+)" \/tmp\/browser-info\.txt/);
-  if (!match?.[1]) throw new Error(`no header grep generated for ${browser}`);
-  return new RegExp(match[1]);
-}
-
-describe("playwright extension dry-run header parsing", () => {
-  const instructions = generatedInstructions({
-    browsers: ["chromium", "firefox", "webkit"],
-    headless: false,
-  });
-  const browsers = Object.keys(HEADERS["1.57"]) as BrowserKey[];
+const browsers = Object.keys(HEADERS["1.57"]) as Array<keyof (typeof HEADERS)["1.57"]>;
 
+describe("playwright extension dry-run header pattern", () => {
   it.each(browsers)("selects the %s block in both output formats", (browser) => {
-    const pattern = headerPattern(instructions, browser);
+    const pattern = new RegExp(dryRunHeaderPattern(browser));
 
     expect(pattern.test(HEADERS["1.57"][browser])).toBe(true);
     expect(pattern.test(HEADERS["1.62"][browser])).toBe(true);
   });
 
   it.each(browsers)("does not select another browser's block for %s", (browser) => {
-    const pattern = headerPattern(instructions, browser);
+    const pattern = new RegExp(dryRunHeaderPattern(browser));
 
     for (const other of browsers.filter((b) => b !== browser)) {
       expect(pattern.test(HEADERS["1.57"][other])).toBe(false);

packages/build/src/extensions/playwright.ts

@@ -196,6 +196,19 @@ export function playwright(options: PlaywrightExtensionOptions = {}) {
   return new PlaywrightExtension(options);
 }
 
+/**
+ * Extended regex selecting a browser's block header in `playwright install --dry-run` output.
+ *
+ * Playwright < 1.58 prints `browser: <name> version <v>`; 1.58+ prints
+ * `<Product> <v> (playwright <name> v<build>)`. The trailing space / `v` keep
+ * `chromium` from matching the `chromium-headless-shell` block.
+ *
+ * @internal
+ */
+export function dryRunHeaderPattern(browser: string): string {
+  return `browser: ${browser} |\\(playwright ${browser} v`;
+}
+
 /**
  * Background:
  *
@@ -317,12 +330,9 @@ class PlaywrightExtension implements BuildExtension {
 
     Array.from(browsersToInstall).forEach((browser) => {
       instructions.push(
-        // Playwright < 1.58 prints `browser: <name> version <v>`; 1.58+ prints
-        // `<Product> <v> (playwright <name> v<build>)`. The trailing space / `v`
-        // keep `chromium` from matching the `chromium-headless-shell` block, and
-        // only the two lines after the header (install location, download url)
+        // Only the two lines after the header (install location, download url)
         // are read, so the window stops there.
-        `RUN grep -A2 -m1 -E "browser: ${browser} |\\(playwright ${browser} v" /tmp/browser-info.txt > /tmp/${browser}-info.txt`,
+        `RUN grep -A2 -m1 -E "${dryRunHeaderPattern(browser)}" /tmp/browser-info.txt > /tmp/${browser}-info.txt`,
 
         `RUN INSTALL_DIR=$(grep "Install location:" /tmp/${browser}-info.txt | cut -d':' -f2- | xargs) && \
           DIR_NAME=$(basename "$INSTALL_DIR") && \