04/03: add test isolation exercise

Author: kettanaito

.gitignore

@@ -15,6 +15,7 @@ __screenshots__
 test-profiles
 coverage
 .vitest-reports
+*.DS_Store
 
 # in a real app you'd want to not commit the .env
 # file as well, but since this is for a workshop

epicshop/generate-tests.js

@@ -0,0 +1,57 @@
+import fs from 'node:fs'
+
+const TEST_COUNT = 500
+
+/**
+ * @param {URL} exerciseDirectory
+ * @param {number} count
+ */
+async function generateTests(exerciseDirectory, count) {
+	const TESTS_DIR = new URL('./tests/', exerciseDirectory)
+
+	const existingTests = fs.globSync('./*.test.ts', {
+		cwd: TESTS_DIR.pathname,
+	})
+	await Promise.all(
+		existingTests.map((filename) => {
+			return fs.promises.rm(new URL(filename, TESTS_DIR))
+		}),
+	)
+
+	await Promise.all(
+		Array.from({ length: count }).map((_, index) => {
+			const filename = `./test-${index.toString().padStart(count.toString().length, '0')}.test.ts`
+			const contents = `\
+test('equals to ${index}', ({ expect }) => {
+	expect(${index}).toBe(${index})
+})
+`
+
+			return fs.promises.writeFile(
+				new URL(filename, TESTS_DIR),
+				contents,
+				'utf8',
+			)
+		}),
+	)
+}
+
+Promise.all([
+	generateTests(
+		new URL(
+			'../exercises/04.performance/03.problem.test-isolation/',
+			import.meta.url,
+		),
+		TEST_COUNT,
+	),
+	generateTests(
+		new URL(
+			'../exercises/04.performance/03.solution.test-isolation/',
+			import.meta.url,
+		),
+		TEST_COUNT,
+	),
+]).catch((error) => {
+	console.error('❌  Failed to generate tests.\n\n', error)
+	process.exit(1)
+})

epicshop/setup.js

@@ -1,4 +1,4 @@
-import { spawnSync } from 'child_process'
+import { spawnSync } from 'node:child_process'
 
 const styles = {
 	// got these from playing around with what I found from:
@@ -34,18 +34,33 @@ if (major < 8 || (major === 8 && minor < 16)) {
 	throw new Error('npm version is out of date')
 }
 
-const command =
-	'npx --yes "https://gist.github.com/kentcdodds/bb452ffe53a5caa3600197e1d8005733" -q'
-console.log(
-	color('subtitle', '      Running the following command: ' + command),
-)
+// Generate test suites for exercises.
+{
+	const result = spawnSync('node ./generate-tests.js', {
+		cwd: new URL('.', import.meta.url),
+		stdio: 'inherit',
+		shell: true,
+	})
 
-const result = spawnSync(command, { stdio: 'inherit', shell: true })
+	if (result.status !== 0) {
+		process.exit(result.status)
+	}
+}
+
+{
+	const command =
+		'npx --yes "https://gist.github.com/kentcdodds/bb452ffe53a5caa3600197e1d8005733" -q'
+	console.log(
+		color('subtitle', '      Running the following command: ' + command),
+	)
+
+	const result = spawnSync(command, { stdio: 'inherit', shell: true })
 
-if (result.status === 0) {
-	console.log(color('success', '✅  Workshop setup complete...'))
-} else {
-	process.exit(result.status)
+	if (result.status === 0) {
+		console.log(color('success', '✅  Workshop setup complete!'))
+	} else {
+		process.exit(result.status)
+	}
 }
 
 /*

exercises/04.performance/03.problem.test-isolation/.gitignore

@@ -0,0 +1,3 @@
+# Ignore the test files for this exercise because
+# they are generated during the setup step.
+/tests/**/*.test.ts

exercises/04.performance/03.problem.test-isolation/README.mdx

@@ -0,0 +1,10 @@
+{
+  "type": "module",
+  "name": "exercises_04.performance_03.problem.test-isolation",
+  "scripts": {
+    "test": "vitest"
+  },
+  "devDependencies": {
+    "vitest": "^3.1.1"
+  }
+}

exercises/04.performance/03.problem.test-isolation/package.json

@@ -0,0 +1,7 @@
+{
+	"extends": "./tsconfig.base.json",
+	"compilerOptions": {
+		"lib": ["ES2023"]
+	},
+	"include": ["vitest.config.ts", "generate-tests.ts"]
+}