Solution

src/ifElse.test.js

@@ -1,9 +1,40 @@
 'use strict';
 
 describe('ifElse', () => {
-  // const { ifElse } = require('./ifElse');
+  const { ifElse } = require('./ifElse');
 
-  it('should ', () => {});
+  it('should call first if condition is true', () => {
+    const condition = () => true;
 
-  // write tests here
+    const first = jest.fn();
+    const second = jest.fn();
+
+    ifElse(condition, first, second);
+
+    expect(first).toHaveBeenCalled();
+    expect(second).not.toHaveBeenCalled();
+  });
+
+  it('should call second if condition is false', () => {
+    const condition = () => false;
+
+    const first = jest.fn();
+    const second = jest.fn();
+
+    ifElse(condition, first, second);
+
+    expect(second).toHaveBeenCalled();
+    expect(first).not.toHaveBeenCalled();
+  });
+
+  it('should not return anything', () => {
+    const condition = () => true;
+
+    const first = jest.fn();
+    const second = jest.fn();
+
+    const result = ifElse(condition, first, second);
+
+    expect(result).toBeUndefined();
+  });
 });