unit test

Author: annajowang

packages/@apphosting/adapter-nextjs/src/overrides.spec.ts

@@ -378,6 +378,67 @@ describe("validateNextConfigOverride", () => {
   });
 });
 
+describe("next config restore", () => {
+  let tmpDir: string;
+  const nextConfigOriginalBody = `
+    // @ts-check
+
+    /** @type {import('next').NextConfig} */
+    const nextConfig = {
+      /* config options here */
+    }
+
+    module.exports = nextConfig
+    `;
+  const nextConfigBody = `
+  // This file was automatically generated by Firebase App Hosting adapter
+  const fahOptimizedConfig = (config) => ({
+    ...config,
+    images: {
+      ...(config.images || {}),
+      ...(config.images?.unoptimized === undefined && config.images?.loader === undefined
+          ? { unoptimized: true }
+          : {}),
+    },
+  });
+
+  const config = typeof originalConfig === 'function'
+    ? async (...args) => {
+        const resolvedConfig = await originalConfig(...args);
+        return fahOptimizedConfig(resolvedConfig);
+      }
+    : fahOptimizedConfig(originalConfig);
+  `;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "test-overrides"));
+  });
+
+  it("handle no original config file found", async () => {
+    const { restoreNextConfig } = await importOverrides;
+    fs.writeFileSync(path.join(tmpDir, "next.config.mjs"), nextConfigBody);
+    await restoreNextConfig(tmpDir, "next.config.mjs");
+
+    const restoredConfig = fs.readFileSync(path.join(tmpDir, "next.config.mjs"), "utf-8");
+    assert.equal(restoredConfig, nextConfigBody);
+  });
+
+  it("handle no config file found", async () => {
+    const { restoreNextConfig } = await importOverrides;
+    assert.doesNotReject(restoreNextConfig(tmpDir, "next.config.mjs"));
+  });
+
+  it("original config file restored", async () => {
+    const { restoreNextConfig } = await importOverrides;
+    fs.writeFileSync(path.join(tmpDir, "next.config.mjs"), nextConfigBody);
+    fs.writeFileSync(path.join(tmpDir, "next.config.original.mjs"), nextConfigOriginalBody);
+    await restoreNextConfig(tmpDir, "next.config.mjs");
+
+    const restoredConfig = fs.readFileSync(path.join(tmpDir, "next.config.mjs"), "utf-8");
+    assert.equal(restoredConfig, nextConfigOriginalBody);
+  });
+});
+
 // Normalize whitespace for comparison
 function normalizeWhitespace(str: string) {
   return str.replace(/\s+/g, " ").trim();

packages/@apphosting/adapter-nextjs/src/overrides.ts

@@ -143,7 +143,8 @@ export async function validateNextConfigOverride(
 }
 
 /**
- *
+ * Restores the user's original Next Config file (next.config.original.[ts|js|mjs])
+ * to leave user code the way we found it.
  */
 export async function restoreNextConfig(projectRoot: string, nextConfigFileName: string) {
   // Check if the file exists in the current working directory