Add specs for history slider (#1053)

* Add specs for history slider

* Remove flow annotation from history-spec.js to make travis happy

* Remove uneccessary imports in history-spec.js

spec/components/result-view/history-spec.js

@@ -0,0 +1,41 @@
+"use babel";
+
+import React from "react";
+import Enzyme, { shallow } from "enzyme";
+
+import History from "../../../lib/components/result-view/history";
+
+describe("History", () => {
+  it("should render and display the current output", () => {
+    const mockStore = {
+      index: 0,
+      outputs: [{}, {}]
+    };
+
+    const component = shallow(<History store={mockStore} />);
+    expect(component.type()).not.toBeNull();
+    expect(component.text()).toContain("1/2");
+  });
+
+  it("should change the index when the arrows are clicked", () => {
+    const mockStore = {
+      index: 0,
+      outputs: [{}, {}],
+      setIndex: v => {
+        mockStore.index = v;
+      },
+      incrementIndex: () => {
+        mockStore.index++;
+      },
+      decrementIndex: () => {
+        mockStore.index--;
+      }
+    };
+
+    const component = shallow(<History store={mockStore} />);
+    component.find(".icon-chevron-right").simulate("click");
+    expect(mockStore.index).toBe(1);
+    component.find(".icon-chevron-left").simulate("click");
+    expect(mockStore.index).toBe(0);
+  });
+});