test: Fix flaky tests after #4811 due to bad assumptions

**Summary**

Tests started failing on Travis after #4811, somewhat randomly, due to the mexpecting the unwrapped
output. This PR fixes those expectations and moves normalize-manifest tests to snapshots since
that's easier than updating 40+ JSON files by hand.

**Test plan**

Tests should pass on all platforms and CI and locally.

__tests__/commands/install/bin-links.js

@@ -31,7 +31,7 @@ function execCommand(cwd: string, binPath: Array<string>, args: Array<string>):
         cwd,
         env: {
           ...process.env,
-          YARN_SILENT: 0,
+          YARN_WRAP_OUTPUT: 1,
         },
       },
       (error, stdout) => {

__tests__/index.js

@@ -34,6 +34,7 @@ async function execCommand(
   return new Promise((resolve, reject) => {
     const cleanedEnv = {...process.env};
     cleanedEnv['YARN_SILENT'] = 0;
+    cleanedEnv['YARN_WRAP_OUTPUT'] = 1;
     delete cleanedEnv['FORCE_COLOR'];
 
     exec(
@@ -121,7 +122,7 @@ test.concurrent('should add package with no-lockfile option', async () => {
   expectAddSuccessfullOutputWithNoLockFile(stdout, 'repeating');
 });
 
-test.concurrent('should add package with frozzen-lockfile option', async () => {
+test.concurrent('should add package with frozen-lockfile option', async () => {
   const stdout = await execCommand('add', ['repeating', '--frozen-lockfile'], 'run-add-option', true);
   expectAddSuccessfullOutputWithNoLockFile(stdout, 'repeating');
 });

__tests__/lifecycle-scripts.js

@@ -20,7 +20,7 @@ async function execCommand(cmd: string, packageName: string, env = process.env):
 
   return new Promise((resolve, reject) => {
     const cleanedEnv = {...env};
-    cleanedEnv['YARN_SILENT'] = 0;
+    cleanedEnv['YARN_WRAP_OUTPUT'] = 1;
     delete cleanedEnv['FORCE_COLOR'];
 
     exec(

__tests__/normalize-manifest.js

@@ -2,7 +2,7 @@
 /* eslint max-len: 0 */
 
 import normalizeManifest from '../src/util/normalize-manifest/index.js';
-import NoopReporter from '../src/reporters/base-reporter.js';
+import {BufferReporter} from '../src/reporters/index.js';
 import Config from '../src/config.js';
 import map from '../src/util/map.js';
 import * as util from '../src/util/normalize-manifest/util.js';
@@ -16,15 +16,7 @@ jasmine.DEFAULT_TIMEOUT_INTERVAL = 60000;
 const fixturesLoc = path.join(__dirname, 'fixtures', 'normalize-manifest');
 
 async function _compareManifests(loc, options = {}): Promise<void> {
-  const actualWarnings = [];
-  const expectedWarnings = options.expectedWarnings || (await fs.readJson(path.join(loc, 'warnings.json')));
-  const reporter = new NoopReporter();
-
-  // $FlowFixMe: Investigate
-  reporter.warn = function(msg) {
-    actualWarnings.push(msg);
-  };
-
+  const reporter = new BufferReporter();
   const config = await Config.create({cwd: loc, globalFolder: options.globalFolder}, reporter);
 
   let actual = await fs.readJson(path.join(loc, 'actual.json'));
@@ -57,7 +49,7 @@ async function _compareManifests(loc, options = {}): Promise<void> {
   }
 
   expect(map(actual)).toEqual(expand(expected));
-  expect(actualWarnings).toEqual(expectedWarnings);
+  expect(reporter.getBuffer().filter(d => d.type === 'warning')).toMatchSnapshot(loc + options.globalFolder);
 }
 
 for (const name of nativeFs.readdirSync(fixturesLoc)) {
@@ -75,7 +67,6 @@ const globalfixturesLoc = path.join(__dirname, 'fixtures', 'normalize-manifest',
 test(
   'license warnings should not be thrown with global commands',
   _compareManifests.bind(null, globalfixturesLoc, {
-    expectedWarnings: [],
     globalFolder: globalfixturesLoc,
   }),
 );

src/reporters/buffer-reporter.js

@@ -9,7 +9,7 @@ type Buffer = Array<{
 }>;
 
 export default class BufferReporter extends JSONReporter {
-  constructor(opts: Object) {
+  constructor(opts?: Object) {
     super(opts);
     this._buffer = [];
   }