Adds a test

__tests__/commands/install/integration.js

@@ -61,6 +61,15 @@ test.concurrent('properly find and save build artifacts', async () => {
   });
 });
 
+test('reading a lockfile should not optimize it', async () => {
+  await runInstall({}, 'lockfile-optimization', async (config, reporter): Promise<void> => {
+    const was = await fs.readFile(`${__dirname}/../../fixtures/install/lockfile-optimization/yarn.lock`);
+    const is = await fs.readFile(`${config.cwd}/yarn.lock`);
+
+    expect(is).toEqual(was);
+  });
+});
+
 test('creates the file in the mirror when fetching a git repository', async () => {
   await runInstall({}, 'install-git', async (config, reporter): Promise<void> => {
     const lockfile = await Lockfile.fromDirectory(config.cwd);

__tests__/fixtures/install/lockfile-optimization/package.json

@@ -0,0 +1,6 @@
+{
+  "dependencies": {
+    "webpack": "1.14.0",
+    "webpack-parallel-uglify-plugin": "0.2.0"
+  }
+}