[_refactored] Scheduler tests to follow Starmap organization

Summary:
We'd like the unit tests to follow the organization of the [Starmap](https://material-motion.gitbooks.io/material-motion-starmap/content/specifications/runtime/scheduler.html), to make it easy to cross-link between them.  To that end, I've refactored these tests by:

- Renaming `Scheduler.test` to `Scheduler-addPlan.test`
- Collapsing all tests to top level `describe` call, combining `beforeEach` calls as needed

Reviewers: featherless, O2 Material Motion

Reviewed By: featherless, O2 Material Motion

Subscribers: featherless

Tags: #material_motion

Differential Revision: http://codereview.cc/D1715

packages/runtime/src/__tests__/Scheduler-addPlan.test.ts

@@ -0,0 +1,124 @@
+/** @license
+ *  Copyright 2016 The Material Motion Authors. All Rights Reserved.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ *  use this file except in compliance with the License. You may obtain a copy
+ *  of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ *  License for the specific language governing permissions and limitations
+ *  under the License.
+ */
+
+import { expect } from 'chai';
+
+import {
+  beforeEach,
+  describe,
+  it,
+} from 'mocha-sugar-free';
+
+import {
+  stub,
+} from 'sinon';
+
+import Scheduler from '../Scheduler';
+
+// chai really doesn't like being imported as an ES2015 module; will be fixed in v4
+require('chai').use(
+  require('sinon-chai')
+);
+
+describe('Scheduler.addPlan',
+  () => {
+    let scheduler;
+    let addPlanSpy;
+    let PerformerSpy;
+    let planWithSpies;
+    let target = {};
+
+    beforeEach(
+      () => {
+        scheduler = new Scheduler();
+
+        addPlanSpy = stub();
+
+        PerformerSpy = stub().returns(
+          {
+            addPlan: addPlanSpy,
+          }
+        );
+
+        planWithSpies = {
+          _performerType: PerformerSpy,
+        }
+      }
+    );
+
+    it(`should require arguments`,
+      () => {
+        expect(
+          () => {
+            scheduler.addPlan();
+          }
+        ).to.throw(`Scheduler.addPlan requires`);
+      }
+    );
+
+    it(`should require a target`,
+      () => {
+        expect(
+          () => {
+            scheduler.addPlan({ plan: planWithSpies });
+          }
+        ).to.throw(`requires a target`);
+      }
+    );
+
+    it(`should require a plan`,
+      () => {
+        expect(
+          () => {
+            scheduler.addPlan({ target });
+          }
+        ).to.throw(`requires a plan`);
+      }
+    );
+
+    it(`should create a performer from plan._performerType`,
+      () => {
+        scheduler.addPlan({ plan: planWithSpies, target });
+
+        expect(planWithSpies._performerType).to.be.calledWithNew;
+      }
+    );
+
+    it(`should recycle performers for the same plan and target`,
+      () => {
+        scheduler.addPlan({ plan: planWithSpies, target });
+        scheduler.addPlan({ plan: planWithSpies, target });
+        expect(PerformerSpy).to.have.been.calledOnce;
+      }
+    );
+
+    it(`should create new performers for each target`,
+      () => {
+        scheduler.addPlan({ plan: planWithSpies, target });
+        scheduler.addPlan({ plan: planWithSpies, target: {} });
+        expect(PerformerSpy).to.have.been.calledTwice;
+      }
+    );
+
+    it(`should call performer.addPlan for each plan`,
+      () => {
+        scheduler.addPlan({ plan: planWithSpies, target });
+        scheduler.addPlan({ plan: planWithSpies, target });
+        expect(addPlanSpy).to.have.been.calledTwice;
+      }
+    );
+  }
+);