add test file

test/common.js

@@ -0,0 +1,56 @@
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import path from 'path';
+import { spawn } from 'child_process';
+import sinon from 'sinon';
+
+const TEST_CACHE_PATH = 'test/sandbox/test-cache';
+
+global.chai = chai;
+
+global.chai.use(chaiAsPromised);
+
+global.sinon = sinon;
+
+global.execAsPromise = (command, args) => {
+  return new Promise((resolve, reject) => {
+    let
+      message = [],
+      process = spawn(command, args);
+
+    process.stderr.on('data', (buffer) => message.push(buffer.toString()));
+
+    process.on('close', (code) => {
+      if (code !== 0) {
+        return reject(new Error(message.join('')));
+      }
+
+      return resolve();
+    });
+  });
+};
+
+global.prepareTestCacheAsDirectory = () => {
+  return global.execAsPromise('mkdir', ['-p', TEST_CACHE_PATH]);
+};
+
+global.prepareTestCacheAsFile = () => {
+  return global.execAsPromise('touch', [TEST_CACHE_PATH]);
+};
+
+global.prepareTestCacheFile = (filename) => {
+  return global.execAsPromise('touch', [path.join(TEST_CACHE_PATH, filename)]);
+};
+
+global.prepareTestCacheAsSymbolicLink = () => {
+  return global.execAsPromise('ln', ['-s', '.', TEST_CACHE_PATH]);
+};
+
+global.removeTestCache = () => {
+  return global.execAsPromise('rm', ['-rf', TEST_CACHE_PATH]);
+};
+
+global.should = chai.should();
+
+global.TEST_CACHE_PATH = TEST_CACHE_PATH;
+