ObjectCache reducer tests & docs

src/app/core/cache/object-cache.reducer.spec.ts

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+import * as deepFreeze from "deep-freeze";
+import { objectCacheReducer } from "./object-cache.reducer";
+import {
+  AddToObjectCacheAction,
+  RemoveFromObjectCacheAction
+} from "./object-cache.actions";
+
+class NullAction extends RemoveFromObjectCacheAction {
+  type = null;
+  payload = null;
+
+  constructor() {
+    super(null);
+  }
+}
+
+describe("objectCacheReducer", () => {
+  const uuid = '1698f1d3-be98-4c51-9fd8-6bfedcbd59b7';
+  const testState = {
+    [uuid]: {
+      data: {
+        uuid: uuid,
+        foo: "bar"
+      },
+      timeAdded: new Date().getTime(),
+      msToLive: 900000
+    }
+  };
+  deepFreeze(testState);
+
+  it("should return the current state when no valid actions have been made", () => {
+    const action = new NullAction();
+    const newState = objectCacheReducer(testState, action);
+
+    expect(newState).toEqual(testState);
+  });
+
+  it("should start with an empty cache", () => {
+    const action = new NullAction();
+    const initialState = objectCacheReducer(undefined, action);
+
+    expect(initialState).toEqual(Object.create(null));
+  });
+
+  it("should add the payload to the cache in response to an ADD action", () => {
+    const state = Object.create(null);
+    const objectToCache = {uuid: uuid};
+    const timeAdded = new Date().getTime();
+    const msToLive = 900000;
+    const action = new AddToObjectCacheAction(objectToCache, timeAdded, msToLive);
+    const newState = objectCacheReducer(state, action);
+
+    expect(newState[uuid].data).toEqual(objectToCache);
+    expect(newState[uuid].timeAdded).toEqual(timeAdded);
+    expect(newState[uuid].msToLive).toEqual(msToLive);
+  });
+
+  it("should overwrite an object in the cache in response to an ADD action if it already exists", () => {
+    const objectToCache = {uuid: uuid, foo: "baz", somethingElse: true};
+    const timeAdded = new Date().getTime();
+    const msToLive = 900000;
+    const action = new AddToObjectCacheAction(objectToCache, timeAdded, msToLive);
+    const newState = objectCacheReducer(testState, action);
+
+    expect(newState[uuid].data['foo']).toBe("baz");
+    expect(newState[uuid].data['somethingElse']).toBe(true);
+  });
+
+  it("should perform the ADD action without affecting the previous state", () => {
+    const state = Object.create(null);
+    const objectToCache = {uuid: uuid};
+    const timeAdded = new Date().getTime();
+    const msToLive = 900000;
+    const action = new AddToObjectCacheAction(objectToCache, timeAdded, msToLive);
+    deepFreeze(state);
+
+    objectCacheReducer(state, action);
+  });
+
+  it("should remove the specified object from the cache in response to the REMOVE action", () => {
+    const action = new RemoveFromObjectCacheAction(uuid);
+    const newState = objectCacheReducer(testState, action);
+
+    expect(testState[uuid]).not.toBeUndefined();
+    expect(newState[uuid]).toBeUndefined();
+  });
+
+  it("shouldn't do anything in response to the REMOVE action for an object that isn't cached", () => {
+    const action = new RemoveFromObjectCacheAction("this isn't cached");
+    const newState = objectCacheReducer(testState, action);
+
+    expect(newState).toEqual(testState);
+  });
+
+  it("should perform the REMOVE action without affecting the previous state", () => {
+    const action = new RemoveFromObjectCacheAction(uuid);
+    //testState has already been frozen above
+    objectCacheReducer(testState, action);
+  });
+
+});