Tests: Cache NextJS builds

Cache the NextJS apps built for testing. The cache is based on the
current NextJS version and a hash of the folder contents. This
guarantees that the app will be rebuilt if the fixture files change
(e.g., modifying one of the pages or the config). Because the building
of NextJS is rather slow, the tests are several times faster when a
cache has been established.

The cache can be busted by running -npm run cleanup-.

Author: FinnWoelm

package-lock.json

@@ -26,6 +26,7 @@
   ],
   "scripts": {
     "format": "prettier --write .",
+    "cleanup": "node ./tests/helpers/clearCache.js",
     "test": "jest --config tests/jest.config.js",
     "cypress:local": "env CYPRESS_DEPLOY=local cypress run --config-file false --config video=false",
     "cypress:netlify": "env CYPRESS_DEPLOY=netlify cypress run --config-file false --config video=false",
@@ -37,6 +38,7 @@
   },
   "devDependencies": {
     "cypress": "^5.1.0",
+    "folder-hash": "^3.3.3",
     "jest": "^26.4.2",
     "netlify-cli": "^2.61.0",
     "next": "^9.5.3",

package.json

@@ -1,14 +1,7 @@
 // Test next-on-netlify when a custom distDir is set in next.config.js
+
 const { parse, join } = require("path");
-const {
-  copySync,
-  emptyDirSync,
-  existsSync,
-  readdirSync,
-  readFileSync,
-  readJsonSync,
-} = require("fs-extra");
-const npmRunBuild = require("./helpers/npmRunBuild");
+const buildNextApp = require("./helpers/buildNextApp");
 
 // The name of this test file (without extension)
 const FILENAME = parse(__filename).name;
@@ -18,49 +11,25 @@ const FILENAME = parse(__filename).name;
 // package.json file.
 const PROJECT_PATH = join(__dirname, "builds", FILENAME);
 
-// The directory that contains the fixtures, such as NextJS pages,
-// NextJS config, and package.json
-const FIXTURE_PATH = join(__dirname, "fixtures");
-
-// Capture the output of `npm run build` to verify successful build
-let BUILD_OUTPUT;
+// Capture the output to verify successful build
+let buildOutput;
 
 beforeAll(
   async () => {
-    // Clear project directory
-    emptyDirSync(PROJECT_PATH);
-    emptyDirSync(join(PROJECT_PATH, "pages"));
-
-    // Copy NextJS pages and config
-    copySync(join(FIXTURE_PATH, "pages"), join(PROJECT_PATH, "pages"));
-    copySync(
-      join(FIXTURE_PATH, "next.config.js-with-distDir.js"),
-      join(PROJECT_PATH, "next.config.js")
-    );
-
-    // Copy package.json
-    copySync(
-      join(FIXTURE_PATH, "package.json"),
-      join(PROJECT_PATH, "package.json")
-    );
-
-    // Invoke `npm run build`: Build Next and run next-on-netlify
-    const { stdout } = await npmRunBuild({ directory: PROJECT_PATH });
-    BUILD_OUTPUT = stdout;
+    buildOutput = await buildNextApp()
+      .forTest(__filename)
+      .withPages("pages-with-gssp-index")
+      .withNextConfig("next.config.js")
+      .withPackageJson("package.json")
+      .build();
   },
   // time out after 180 seconds
   180 * 1000
 );
 
-describe("Next", () => {
+describe("next-on-netlify", () => {
   test("builds successfully", () => {
-    // NextJS output
-    expect(BUILD_OUTPUT).toMatch("Creating an optimized production build...");
-    expect(BUILD_OUTPUT).toMatch("Finalizing page optimization...");
-    expect(BUILD_OUTPUT).toMatch("First Load JS shared by all");
-
-    // Next on Netlify output
-    expect(BUILD_OUTPUT).toMatch("Next on Netlify");
-    expect(BUILD_OUTPUT).toMatch("Success! All done!");
+    expect(buildOutput).toMatch("Next on Netlify");
+    expect(buildOutput).toMatch("Success! All done!");
   });
 });

tests/customNextDistDir.test.js

@@ -1,12 +1,8 @@
 // Test next-on-netlify when a custom distDir is set in next.config.js
+
 const { parse, join } = require("path");
-const {
-  copySync,
-  emptyDirSync,
-  readFileSync,
-  writeFileSync,
-} = require("fs-extra");
-const npmRunBuild = require("./helpers/npmRunBuild");
+const { readFileSync } = require("fs-extra");
+const buildNextApp = require("./helpers/buildNextApp");
 
 // The name of this test file (without extension)
 const FILENAME = parse(__filename).name;
@@ -16,60 +12,27 @@ const FILENAME = parse(__filename).name;
 // package.json file.
 const PROJECT_PATH = join(__dirname, "builds", FILENAME);
 
-// The directory that contains the fixtures, such as NextJS pages,
-// NextJS config, and package.json
-const FIXTURE_PATH = join(__dirname, "fixtures");
-
-// Capture the output of `npm run build` to verify successful build
-let BUILD_OUTPUT;
+// Capture the output to verify successful build
+let buildOutput;
 
 beforeAll(
   async () => {
-    // Clear project directory
-    emptyDirSync(PROJECT_PATH);
-    emptyDirSync(join(PROJECT_PATH, "pages"));
-
-    // Copy NextJS pages and config
-    copySync(
-      join(FIXTURE_PATH, "pages-with-static-props-index"),
-      join(PROJECT_PATH, "pages")
-    );
-    copySync(
-      join(FIXTURE_PATH, "next.config.js"),
-      join(PROJECT_PATH, "next.config.js")
-    );
-
-    // Copy package.json
-    copySync(
-      join(FIXTURE_PATH, "package.json"),
-      join(PROJECT_PATH, "package.json")
-    );
-
-    // Create a _redirects file
-    writeFileSync(
-      join(PROJECT_PATH, "_redirects"),
-      "# Custom Redirect Rules\n" +
-        "https://old.example.com/* https://new.example.com/:splat 301!\n"
-    );
-
-    // Invoke `npm run build`: Build Next and run next-on-netlify
-    const { stdout } = await npmRunBuild({ directory: PROJECT_PATH });
-    BUILD_OUTPUT = stdout;
+    buildOutput = await buildNextApp()
+      .forTest(__filename)
+      .withPages("pages-with-static-props-index")
+      .withNextConfig("next.config.js")
+      .withPackageJson("package.json")
+      .withFile("_redirects")
+      .build();
   },
   // time out after 180 seconds
   180 * 1000
 );
 
-describe("Next", () => {
+describe("next-on-netlify", () => {
   test("builds successfully", () => {
-    // NextJS output
-    expect(BUILD_OUTPUT).toMatch("Creating an optimized production build...");
-    expect(BUILD_OUTPUT).toMatch("Finalizing page optimization...");
-    expect(BUILD_OUTPUT).toMatch("First Load JS shared by all");
-
-    // Next on Netlify output
-    expect(BUILD_OUTPUT).toMatch("Next on Netlify");
-    expect(BUILD_OUTPUT).toMatch("Success! All done!");
+    expect(buildOutput).toMatch("Next on Netlify");
+    expect(buildOutput).toMatch("Success! All done!");
   });
 });
 

tests/customRedirects.test.js

@@ -1,14 +1,13 @@
 // Test default next-on-netlify configuration
+
 const { parse, join } = require("path");
 const {
-  copySync,
-  emptyDirSync,
   existsSync,
   readdirSync,
   readFileSync,
   readJsonSync,
 } = require("fs-extra");
-const npmRunBuild = require("./helpers/npmRunBuild");
+const buildNextApp = require("./helpers/buildNextApp");
 
 // The name of this test file (without extension)
 const FILENAME = parse(__filename).name;
@@ -18,70 +17,46 @@ const FILENAME = parse(__filename).name;
 // package.json file.
 const PROJECT_PATH = join(__dirname, "builds", FILENAME);
 
-// The directory that contains the fixtures, such as NextJS pages,
-// NextJS config, and package.json
-const FIXTURE_PATH = join(__dirname, "fixtures");
-
-// Capture the output of `npm run build` to verify successful build
-let BUILD_OUTPUT;
+// Capture the output to verify successful build
+let buildOutput;
 
 beforeAll(
   async () => {
-    // Clear project directory
-    emptyDirSync(PROJECT_PATH);
-    emptyDirSync(join(PROJECT_PATH, "pages"));
-
-    // Copy NextJS pages and config
-    copySync(join(FIXTURE_PATH, "pages"), join(PROJECT_PATH, "pages"));
-    copySync(
-      join(FIXTURE_PATH, "next.config.js"),
-      join(PROJECT_PATH, "next.config.js")
-    );
-
-    // Copy package.json
-    copySync(
-      join(FIXTURE_PATH, "package.json"),
-      join(PROJECT_PATH, "package.json")
-    );
-
-    // Copy image.png to public folder
-    copySync(
-      join(FIXTURE_PATH, "image.png"),
-      join(PROJECT_PATH, "public", "image.png")
-    );
-
-    // Invoke `npm run build`: Build Next and run next-on-netlify
-    const { stdout } = await npmRunBuild({ directory: PROJECT_PATH });
-    BUILD_OUTPUT = stdout;
+    buildOutput = await buildNextApp()
+      .forTest(__filename)
+      .withPages("pages")
+      .withNextConfig("next.config.js")
+      .withPackageJson("package.json")
+      .withFile("image.png", join("public", "image.png"))
+      .build();
   },
   // time out after 180 seconds
   180 * 1000
 );
 
-describe("Next", () => {
+describe("next-on-netlify", () => {
   test("builds successfully", () => {
-    // NextJS output
-    expect(BUILD_OUTPUT).toMatch("Creating an optimized production build...");
-    expect(BUILD_OUTPUT).toMatch("Finalizing page optimization...");
-    expect(BUILD_OUTPUT).toMatch("First Load JS shared by all");
+    expect(buildOutput).toMatch("Next on Netlify");
+    expect(buildOutput).toMatch("Success! All done!");
+  });
+});
 
-    // Next on Netlify output
-    expect(BUILD_OUTPUT).toMatch("Next on Netlify");
-    expect(BUILD_OUTPUT).toMatch("Copying public/ folder to out_publish/");
-    expect(BUILD_OUTPUT).toMatch(
-      "Copying static NextJS assets to out_publish/"
-    );
-    expect(BUILD_OUTPUT).toMatch(
+describe("next-on-netlify", () => {
+  test("builds successfully", () => {
+    expect(buildOutput).toMatch("Next on Netlify");
+    expect(buildOutput).toMatch("Copying public/ folder to out_publish/");
+    expect(buildOutput).toMatch("Copying static NextJS assets to out_publish/");
+    expect(buildOutput).toMatch(
       "Setting up SSR pages and SSG pages with fallback as Netlify Functions in out_functions/"
     );
-    expect(BUILD_OUTPUT).toMatch(
+    expect(buildOutput).toMatch(
       "Copying pre-rendered SSG pages to out_publish/ and JSON data to out_publish/_next/data/"
     );
-    expect(BUILD_OUTPUT).toMatch(
+    expect(buildOutput).toMatch(
       "Writing pre-rendered HTML pages to out_publish/"
     );
-    expect(BUILD_OUTPUT).toMatch("Setting up redirects");
-    expect(BUILD_OUTPUT).toMatch("Success! All done!");
+    expect(buildOutput).toMatch("Setting up redirects");
+    expect(buildOutput).toMatch("Success! All done!");
   });
 });
 

tests/defaults.test.js

@@ -0,0 +1,2 @@
+# Custom Redirect Rules
+https://old.example.com/* https://new.example.com/:splat 301!

tests/fixtures/_redirects

@@ -1,7 +1,7 @@
 {
   "name": "next-on-netlify-test",
   "scripts": {
-    "build": "../../../node_modules/.bin/next build",
-    "postbuild": "node ../../../next-on-netlify"
+    "next-build": "../../../../node_modules/.bin/next build",
+    "next-on-netlify": "node ../../../next-on-netlify"
   }
 }

tests/fixtures/package.json

@@ -0,0 +1,3 @@
+const Index = () => <p>This page is pre-rendered.</p>;
+
+export default Index;