Update docs

test/utils/Base64.test.js

@@ -0,0 +1,33 @@
+const { expect } = require('chai');
+
+const Base64 = artifacts.require('$Base64');
+
+contract('Strings', function () {
+  beforeEach(async function () {
+    this.base64 = await Base64.new();
+  });
+
+  describe('from bytes - base64', function () {
+    it('converts to base64 encoded string with double padding', async function () {
+      const TEST_MESSAGE = 'test';
+      const input = web3.utils.asciiToHex(TEST_MESSAGE);
+      expect(await this.base64.$encode(input)).to.equal('dGVzdA==');
+    });
+
+    it('converts to base64 encoded string with single padding', async function () {
+      const TEST_MESSAGE = 'test1';
+      const input = web3.utils.asciiToHex(TEST_MESSAGE);
+      expect(await this.base64.$encode(input)).to.equal('dGVzdDE=');
+    });
+
+    it('converts to base64 encoded string without padding', async function () {
+      const TEST_MESSAGE = 'test12';
+      const input = web3.utils.asciiToHex(TEST_MESSAGE);
+      expect(await this.base64.$encode(input)).to.equal('dGVzdDEy');
+    });
+
+    it('empty bytes', async function () {
+      expect(await this.base64.$encode([])).to.equal('');
+    });
+  });
+});