Move ERC20 tests to ERC20 custom folder (#772)

test/token/ERC20/BasicToken.test.js

@@ -0,0 +1,82 @@
+import assertRevert from '../../helpers/assertRevert';
+const BasicToken = artifacts.require('BasicTokenMock');
+
+contract('StandardToken', function ([_, owner, recipient, anotherAccount]) {
+  const ZERO_ADDRESS = '0x0000000000000000000000000000000000000000';
+
+  beforeEach(async function () {
+    this.token = await BasicToken.new(owner, 100);
+  });
+
+  describe('total supply', function () {
+    it('returns the total amount of tokens', async function () {
+      const totalSupply = await this.token.totalSupply();
+
+      assert.equal(totalSupply, 100);
+    });
+  });
+
+  describe('balanceOf', function () {
+    describe('when the requested account has no tokens', function () {
+      it('returns zero', async function () {
+        const balance = await this.token.balanceOf(anotherAccount);
+
+        assert.equal(balance, 0);
+      });
+    });
+
+    describe('when the requested account has some tokens', function () {
+      it('returns the total amount of tokens', async function () {
+        const balance = await this.token.balanceOf(owner);
+
+        assert.equal(balance, 100);
+      });
+    });
+  });
+
+  describe('transfer', function () {
+    describe('when the recipient is not the zero address', function () {
+      const to = recipient;
+
+      describe('when the sender does not have enough balance', function () {
+        const amount = 101;
+
+        it('reverts', async function () {
+          await assertRevert(this.token.transfer(to, amount, { from: owner }));
+        });
+      });
+
+      describe('when the sender has enough balance', function () {
+        const amount = 100;
+
+        it('transfers the requested amount', async function () {
+          await this.token.transfer(to, amount, { from: owner });
+
+          const senderBalance = await this.token.balanceOf(owner);
+          assert.equal(senderBalance, 0);
+
+          const recipientBalance = await this.token.balanceOf(to);
+          assert.equal(recipientBalance, amount);
+        });
+
+        it('emits a transfer event', async function () {
+          const { logs } = await this.token.transfer(to, amount, { from: owner });
+
+          assert.equal(logs.length, 1);
+          assert.equal(logs[0].event, 'Transfer');
+          assert.equal(logs[0].args.from, owner);
+          assert.equal(logs[0].args.to, to);
+          assert(logs[0].args.value.eq(amount));
+        });
+      });
+    });
+
+    describe('when the recipient is the zero address', function () {
+      const to = ZERO_ADDRESS;
+
+      it('reverts', async function () {
+        await assertRevert(this.token.transfer(to, 100, { from: owner }));
+      });
+    });
+  });
+});