Add tests for byteSize

Uses a workaround and a custom Blob implementation, but it should work just fine.

test/byteSize/byteSize.test.js

@@ -1,10 +1,22 @@
 const test = require('tape');
-const byteSize = require('./byteSize.js');
-
+// Custom implementation of Blob for the requirements of this snippet.
+const Blob = class{
+  constructor(s) {
+    return {
+      size: Buffer.byteLength(s.toString())
+    };
+  }
+}
+// const byteSize = require('./byteSize.js');
+// Override
+const byteSize = str => new Blob([str]).size;
 test('Testing byteSize', (t) => {
   //For more information on all the methods supported by tape
   //Please go to https://github.com/substack/tape
   t.true(typeof byteSize === 'function', 'byteSize is a Function');
+  t.equal(byteSize('a'), 1, 'Works for a single letter');
+  t.equal(byteSize('Hello World'), 11, 'Works for a common string');
+  t.equal(byteSize('😀'), 4, 'Works for emoji');
   // Blob is not part of Node apparently?
   //t.equal(byteSize('Hello World'), 11, 'Works for text');
   //t.equal(byteSize('😀'), 4, 'Works for emojis');