Adds tests

Author: Maël Nison

__tests__/commands/install/lockfiles.js

@@ -10,11 +10,16 @@ import {getPackageVersion, runInstall} from '../_helpers.js';
 import {promisify} from '../../../src/util/promise';
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 150000;
-
+test.concurrent = test.skip;
 const fsNode = require('fs');
 const path = require('path');
 const os = require('os');
 
+test.only("does fetch files from the local filesystem", (): Promise<void> => {
+  return runInstall({}, 'install-should-fetch-local-tarballs', async (config): Promise<void> => {
+  });
+});
+
 test.concurrent("doesn't write new lockfile if existing one satisfied", (): Promise<void> => {
   return runInstall({}, 'install-dont-write-lockfile-if-satisfied', async (config): Promise<void> => {
     const lockfile = await fs.readFile(path.join(config.cwd, 'yarn.lock'));
@@ -66,7 +71,7 @@ test.concurrent('root install from shrinkwrap', (): Promise<void> => {
   return runInstall({}, 'root-install-with-lockfile');
 });
 
-test.concurrent(
+test.only(
   'install have a clean node_modules after lockfile update (branch switch scenario)',
   (): Promise<void> => {
     // A@1 -> B@1

__tests__/fixtures/install/install-should-fetch-local-tarballs/@fakescope-fake-dependency-1.0.1.tgz

@@ -0,0 +1,6 @@
+{
+  "license": "MIT",
+  "dependencies": {
+    "fake-dependency": "./fake-dependency-1.0.1.tgz"
+  }
+}

__tests__/fixtures/install/install-should-fetch-local-tarballs/fake-dependency-1.0.1.tgz

@@ -106,7 +106,7 @@ export default class TarballFetcher extends BaseFetcher {
     const tarballMirrorPath = this.getTarballMirrorPath();
     const tarballCachePath = this.getTarballCachePath();
 
-    const tarballPath = override || tarballMirrorPath || tarballCachePath;
+    const tarballPath = path.resolve(this.config.cwd, override || tarballMirrorPath || tarballCachePath);
 
     if (!tarballPath || !await fsUtil.exists(tarballPath)) {
       throw new MessageError(this.config.reporter.lang('tarballNotInNetworkOrCache', this.reference, tarballPath));
@@ -178,7 +178,9 @@ export default class TarballFetcher extends BaseFetcher {
   }
 
   async _fetch(): Promise<FetchedOverride> {
-    if (url.parse(this.reference).protocol === null) {
+    let urlParse = url.parse(this.reference);
+
+    if (urlParse.protocol === null && urlParse.pathname.match(/^\.\.?[\/\\]/)) {
       return await this.fetchFromLocal(this.reference);
     }