chore: add integration tests

Author: jamesgeorge007

.eslintrc.json

@@ -4,7 +4,8 @@
     "browser": true,
     "commonjs": true,
     "node": true,
-    "es6": true
+    "es6": true,
+    "jest": true
   },
   "parserOptions": {
     "ecmaVersion": 2018

package.json

@@ -15,6 +15,7 @@
     "screencast": "node ./tasks/screencast.js",
     "screencast:error": "svg-term --cast jyu19xGl88FQ3poMY8Hbmfw8y --out screencast-error.svg --window --at 12000 --no-cursor",
     "alex": "alex .",
+    "test:integration": "jest test/integration",
     "test": "cd packages/react-scripts && node bin/react-scripts.js test",
     "format": "prettier --write 'packages/*/*.js' 'packages/*/!(node_modules)/**/*.js'",
     "compile:lockfile": "node tasks/compile-lockfile.js"

test/integration/index.test.js

@@ -0,0 +1,92 @@
+'use strict';
+
+const execa = require('execa');
+const { mkdirp, remove, writeFileSync } = require('fs-extra');
+const { join } = require('path');
+
+const cli = require.resolve('create-react-app/index.js');
+
+jest.setTimeout(1000 * 60 * 5);
+
+const projectName = 'test-app';
+const genPath = join(__dirname, projectName);
+
+const generatedFiles = ['.gitignore', 'package.json', 'src', 'yarn.lock'];
+
+beforeEach(() => remove(genPath));
+afterEach(() => remove(genPath));
+
+const run = (args, options) => execa('node', [cli].concat(args), options);
+
+describe('create-react-app', () => {
+  it('asks to supply an argument if none supplied', async () => {
+    const { stderr } = await run([], { reject: false });
+    expect(stderr).toContain('Please specify the project directory');
+  });
+
+  it('creates a project on supplying a name as the argument', async () => {
+    await run([projectName], { cwd: __dirname });
+
+    // Assert for the generated files
+    generatedFiles.forEach(file => expect(join(genPath, file)).toBeTruthy());
+  });
+
+  it('warns about conflicting files in path', async () => {
+    // Create the temporary directory
+    await mkdirp(genPath);
+
+    // Create a package.json file
+    const pkgJson = join(genPath, 'package.json');
+    writeFileSync(pkgJson, '{ "foo": "bar" }');
+
+    const { stdout } = await run([projectName], {
+      cwd: __dirname,
+      reject: false,
+    });
+
+    // Assert for the expected message
+    expect(stdout).toContain(
+      `The directory ${projectName} contains files that could conflict`
+    );
+  });
+
+  it('creates a project in the current directory', async () => {
+    // Create temporary directory
+    await mkdirp(genPath);
+
+    // Create a project in the current directory
+    await run(['.'], { cwd: genPath });
+
+    // Assert for the generated files
+    generatedFiles.forEach(file => expect(join(genPath, file)).toBeTruthy());
+  });
+
+  it('uses npm as the package manager', async () => {
+    await run([projectName, '--use-npm'], {
+      cwd: __dirname,
+      stdio: 'inherit',
+    });
+
+    // Assert for the generated files
+    const generatedFilesWithNpm = [
+      ...generatedFiles.filter(file => file !== 'yarn.lock'),
+      'package-lock.json',
+    ];
+
+    generatedFilesWithNpm.forEach(file =>
+      expect(join(genPath, file)).toBeTruthy()
+    );
+  });
+
+  it('creates a project in the current based on the typescript template', async () => {
+    await run([projectName, '--template', 'typescript'], {
+      cwd: __dirname,
+      stdio: 'inherit',
+    });
+
+    // Assert for the generated files
+    [...generatedFiles, 'tsconfig.json'].forEach(file =>
+      expect(join(genPath, file)).toBeTruthy()
+    );
+  });
+});