feat: rewrite programming-challenges CLI (#3)

cli/utils/__test__/copyDirectory.test.ts

@@ -0,0 +1,38 @@
+import fsMock from 'mock-fs'
+import fs from 'fs'
+
+import { copyDirectory } from '../copyDirectory'
+
+describe('utils/copyDirectory', () => {
+  afterEach(async () => {
+    fsMock.restore()
+  })
+
+  it('copy the files', async () => {
+    fsMock({
+      '/source': {
+        'default.png': '',
+        'index.ts': '',
+        '.npmignore': ''
+      },
+      '/destination': {}
+    })
+
+    let destinationDirectoryContent = await fs.promises.readdir('/destination')
+    let sourceDirectoryContent = await fs.promises.readdir('/source')
+    expect(destinationDirectoryContent.length).toEqual(0)
+    expect(sourceDirectoryContent.length).toEqual(3)
+
+    await copyDirectory('/source', '/destination')
+    destinationDirectoryContent = await fs.promises.readdir('/destination')
+    sourceDirectoryContent = await fs.promises.readdir('/source')
+    expect(destinationDirectoryContent.length).toEqual(3)
+    expect(sourceDirectoryContent.length).toEqual(3)
+    expect(destinationDirectoryContent).toEqual(
+      expect.arrayContaining(['default.png', 'index.ts', '.npmignore'])
+    )
+    expect(sourceDirectoryContent).toEqual(
+      expect.arrayContaining(['default.png', 'index.ts', '.npmignore'])
+    )
+  })
+})