[isomorphic-core] Make sure specs can run without electron

Summary:
Isomorphic-core should be functional outside of the client environment

Depends on D4056

Test Plan: Run the test suite

Reviewers: evan, spang, juan

Reviewed By: spang, juan

Differential Revision: https://phab.nylas.com/D4062

packages/isomorphic-core/package.json

@@ -3,6 +3,13 @@
   "version": "0.0.1",
   "description": "Packages use isomorphically on n1-cloud and client-sync",
   "main": "index.js",
+  "scripts": {
+    "test": "babel-node spec/run.es6"
+  },
+  "devDependencies": {
+    "babel-cli": "6.x.x",
+    "jasmine": "2.x.x"
+  },
   "dependencies": {
     "atob": "2.0.3",
     "imap": "github:jstejada/node-imap#fix-parse-body-list",

packages/isomorphic-core/spec/jasmine/extensions.es6

@@ -1,5 +1,8 @@
+import applyPolyfills from './polyfills'
+
 export default class JasmineExtensions {
   extend({beforeEach, afterEach} = {}) {
+    applyPolyfills()
     global.it = this._makeItAsync(global.it)
     global.fit = this._makeItAsync(global.fit)
     global.beforeAll = this._makeEachOrAllFnAsync(global.beforeAll)

packages/isomorphic-core/spec/jasmine/polyfills.es6

@@ -0,0 +1,19 @@
+// We use Jasmine 1 in the client tests and Jasmine 2 in the cloud tests,
+// but isomorphic-core tests need to be run in both environments. Tests in
+// isomorphic-core should use Jasmine 1 syntax, and then we can add polyfills
+// here to make sure that they exist when we run in a Jasmine 2 environment.
+
+export default function applyPolyfills() {
+  const origSpyOn = global.spyOn;
+  // There's no prototype to modify, so we have to modify the return
+  // values of spyOn as they're created.
+  global.spyOn = (object, methodName) => {
+    const originalValue = object[methodName]
+    const spy = origSpyOn(object, methodName)
+    object[methodName].originalValue = originalValue;
+    spy.andReturn = spy.and.returnValue;
+    spy.andCallFake = spy.and.callFake;
+    Object.defineProperty(spy.calls, 'length', {get: function getLength() { return this.count(); }})
+    return spy;
+  }
+}

packages/isomorphic-core/spec/run.es6

@@ -0,0 +1,2 @@
+import executeJasmine from './jasmine/execute'
+executeJasmine()