Fix .gitignore: stop tracking ignored files

backend/lib/openzeppelin-contracts/test/token/ERC20/presets/ERC20PresetFixedSupply.test.js

@@ -0,0 +1,42 @@
+const { BN, constants, expectEvent } = require('@openzeppelin/test-helpers');
+const { ZERO_ADDRESS } = constants;
+
+const { expect } = require('chai');
+
+const ERC20PresetFixedSupply = artifacts.require('ERC20PresetFixedSupply');
+
+contract('ERC20PresetFixedSupply', function (accounts) {
+  const [deployer, owner] = accounts;
+
+  const name = 'PresetFixedSupply';
+  const symbol = 'PFS';
+
+  const initialSupply = new BN('50000');
+  const amount = new BN('10000');
+
+  before(async function () {
+    this.token = await ERC20PresetFixedSupply.new(name, symbol, initialSupply, owner, { from: deployer });
+  });
+
+  it('deployer has the balance equal to initial supply', async function () {
+    expect(await this.token.balanceOf(owner)).to.be.bignumber.equal(initialSupply);
+  });
+
+  it('total supply is equal to initial supply', async function () {
+    expect(await this.token.totalSupply()).to.be.bignumber.equal(initialSupply);
+  });
+
+  describe('burning', function () {
+    it('holders can burn their tokens', async function () {
+      const remainingBalance = initialSupply.sub(amount);
+      const receipt = await this.token.burn(amount, { from: owner });
+      expectEvent(receipt, 'Transfer', { from: owner, to: ZERO_ADDRESS, value: amount });
+      expect(await this.token.balanceOf(owner)).to.be.bignumber.equal(remainingBalance);
+    });
+
+    it('decrements totalSupply', async function () {
+      const expectedSupply = initialSupply.sub(amount);
+      expect(await this.token.totalSupply()).to.be.bignumber.equal(expectedSupply);
+    });
+  });
+});