test CodeBlock

frontend/src/Documents/CodeBlock.tsx

@@ -1,6 +1,6 @@
 /* tslint:disable: blueprint-html-components */
 
-import hljs from "highlight.js";
+import * as hljs from "highlight.js";
 import * as React from "react";
 
 import "./CodeBlock.scss";

frontend/src/Documents/tests/CodeBlock.test.tsx

@@ -0,0 +1,27 @@
+import { mount } from "enzyme";
+import * as React from "react";
+
+import * as hljs from "highlight.js";
+import { CodeBlock } from "../CodeBlock";
+
+const highlightSpy = jest.spyOn(hljs, "highlightBlock");
+
+afterEach(() => {
+    jest.restoreAllMocks();
+});
+
+describe("<CodeBlock />", () => {
+    it("should render code and highlight it when updated", () => {
+        const text1 = `console.log("Hello")`;
+        const text2 = `console.log("world")`;
+        const wrapper = mount(<CodeBlock value={text1} language="js" />);
+
+        expect(wrapper.find("pre")).toHaveLength(1);
+        expect(wrapper.text()).toBe(text1);
+        expect(highlightSpy).toHaveBeenCalledTimes(1);
+
+        wrapper.setProps({ value: text2, language: "js" });
+        expect(wrapper.text()).toBe(text2);
+        expect(highlightSpy).toHaveBeenCalledTimes(2);
+    });
+});