solution

src/ifElse.test.js

@@ -1,11 +1,53 @@
-'use strict';
+"use strict";
 
-describe('ifElse', () => {
-  // const { ifElse } = require('./ifElse');
+describe(`ifElse`, () => {
+  const { ifElse } = require(`./ifElse`);
 
-  it('should ', () => {
+  it(`should be a function`, () => {
+    expect(ifElse).toBeInstanceOf(Function);
+  });
+
+  it(`the first function must be called`, () => {
+    const condition = () => true;
+    let count = null;
+
+    const first = () => {
+      count = 1;
+    };
 
+    const second = () => {
+      count = 2;
+    };
+
+    ifElse(condition, first, second);
+    expect(count).toBe(1);
   });
 
-  // write tests here
+  it(`the second function must be called`, () => {
+    const condition = () => false;
+    let count = null;
+
+    const first = () => {
+      count = 1;
+    };
+
+    const second = () => {
+      count = 2;
+    };
+
+    ifElse(condition, first, second);
+    expect(count).toBe(2);
+  });
+
+  it(`should return undefined`, () => {
+    const result = ifElse(
+      () => Math.random() > 0.5,
+      // eslint-disable-next-line no-console
+      () => console.log(1),
+      // eslint-disable-next-line no-console
+      () => console.log(2),
+    );
+
+    expect(result).toBeUndefined();
+  });
 });