Learn more methods in jest

docs/002/__test__/sum.test.js

@@ -7,12 +7,12 @@ const sum = require("../sum");
  */
 
 describe("Test sum function", () => {
-  describe("Check if no number passed or one number only", () => {
+  describe.only("Check if no number passed or one number only", () => {
     it("Should return 0 if no argument passed.", () => {
       expect(sum()).toBe(0);
     });
 
-    it("Should return number", () => {
+    it.skip("Should return number", () => {
       expect(sum(10)).toBe(10);
     });
   });

docs/004/__test_/run.testt.js

@@ -0,0 +1,28 @@
+/**
+ * beforeAll(fn, timeout)
+ * beforeEach(fn, timeout)
+ */
+
+function check() {
+  return 1;
+}
+
+beforeAll(() => {
+  /**
+   * Used with
+   * 1- Connect to database.
+   * 2- Empty testing table
+   * 3- Add dummy data for testing
+   * 4- Prepare everything before testing
+   */
+  expect(check()).toBe(1);
+});
+
+afterAll(() => {
+  /**
+   * Used with
+   * 1- Clean database
+   * 2- Clean cache
+   */
+  expect(check()).toBe(1);
+});

docs/005/__test__/all.test.js

@@ -0,0 +1,64 @@
+const allData = require("../all");
+
+test("Check if array contain 6 elements", () => {
+  expect(allData.length).toBe(5);
+});
+
+test("Check if array contain 6 elements but with different method", () => {
+  expect(allData).toHaveLength(5);
+});
+
+test("Check if array contain number 4", () => {
+  expect(allData).toContain(4);
+});
+
+test("Check if array contain only number [1st method]", () => {
+  for (let i = 0; i < allData.length; i++) {
+    expect(isNaN(allData[i])).toBe(false);
+  }
+});
+
+test("Check if array contain only number [2nd method]", () => {
+  for (let i = 0; i < allData.length; i++) {
+    expect(isNaN(allData[i])).toBeFalsy();
+  }
+});
+
+test("Check if array contain only number [3rd method]", () => {
+  for (let i = 0; i < allData.length; i++) {
+    expect(isNaN(allData[i])).not.toBeTruthy();
+  }
+});
+
+test("Check if array first element is larger than 0", () => {
+  expect(allData[0]).toBeGreaterThanOrEqual(1);
+});
+
+test("Check if array first element is less than 10", () => {
+  expect(allData[0]).toBeLessThanOrEqual(10);
+});
+
+test("Check for undefined", () => {
+  expect(allData[10]).toBeUndefined();
+});
+
+test("Check for substring inside string by RegExp", () => {
+  let myString = "I love Jest";
+  expect(myString).toMatch(/Jest/);
+});
+
+test("Check for property age", () => {
+  let myObject = {
+    name: "Ahmed",
+    age: 30,
+  };
+  expect(myObject).toHaveProperty("age");
+});
+
+test("Check for property age that have value of 30", () => {
+  let myObject = {
+    name: "Ahmed",
+    age: 30,
+  };
+  expect(myObject).toHaveProperty("age", 30);
+});

docs/005/all.js

@@ -0,0 +1,3 @@
+const allData = [1, 2, 3, 4, 5];
+
+module.exports = allData;