Adding uppercase skeleton and its test

lib/uppercase.js

@@ -0,0 +1,7 @@
+// Write a function that returns the specified string in uppercase
+// Parameter S is a String.
+function uppercase(s) {
+	// Your code goes here
+}
+
+module.exports = uppercase;

test/uppercase.test.js

@@ -0,0 +1,17 @@
+const { uppercase } = require('../lib');
+
+test('string "abc" uppercased equals "ABC"', () => {
+  expect(uppercase('abc')).toBe('ABC');
+});
+
+test('empty string uppercased is still empty string', () => {
+  expect(uppercase('')).toBe('');
+});
+
+test('string "Symbols and punctuation (!@#$%) stay the same." uppercased equals "SYMBOLS AND PUNCTUATION (!@#$%) STAY THE SAME."', () => {
+  expect(uppercase('Symbols and punctuation (!@#$%) stay the same.')).toBe('SYMBOLS AND PUNCTUATION (!@#$%) STAY THE SAME.');
+});
+
+test('string "Special characters (á, é, ç, etc.) do change" uppercased equals "SPECIAL CHARACTERS (Á, É, Ç, ETC.) DO CHANGE"', () => {
+  expect(uppercase('Special characters (á, é, ç, etc.) do change')).toBe('SPECIAL CHARACTERS (Á, É, Ç, ETC.) DO CHANGE');
+});