fix(add all tests): all tests for multiply, divide, percent, mod

jest.config.js

@@ -22,7 +22,7 @@ module.exports = {
 
   // An array of glob patterns indicating a set of files for which coverage information should be collected
   collectCoverageFrom: [
-    "src/*.js"
+    "dist/*.js"
   ],
 
   // The directory where Jest should output its coverage files

test/index.test.js

@@ -1,4 +1,4 @@
-const { plus, minus, multiply, diff, divide, percent } = require('../dist/index.js');
+const { plus, minus, multiply, diff, divide, mod, percent } = require('../dist/index.js');
 
 test('adds 1 + 2 to equal 3', () => {
     expect(plus(1, 2)).toBe(3);
@@ -12,3 +12,23 @@ test('diff 10, 2 to equal 8', () => {
     expect(diff(10, 2)).toBe(8);
     expect(diff(10, 18)).toBe(8);
 });
+
+test('multiply 2 and 5 to equal 10', () => {
+    expect(multiply(2, 5)).toBe(10);
+});
+
+test('divide 20 and 5 to equal 4', () => {
+    expect(divide(20, 5)).toBe(4);
+});
+
+test('mod 22 and 5 to equal 2', () => {
+    expect(mod(22, 5)).toBe(2);
+});
+
+test('percent library test', () => {
+    expect(percent(7, 18, "%", 2)).toBe("38.89%");
+    expect(percent(19, 12, null, 5)).toBe("158.33333");
+    expect(percent(7, 10, null, 2)).toBe("70.00");
+    expect(percent(17, 12, null, null)).toBe("142");
+});
+