Fix .gitignore: stop tracking ignored files

backend/lib/openzeppelin-contracts/test/token/ERC20/extensions/ERC20Capped.test.js

@@ -0,0 +1,23 @@
+const { ether, expectRevert } = require('@openzeppelin/test-helpers');
+const { shouldBehaveLikeERC20Capped } = require('./ERC20Capped.behavior');
+
+const ERC20Capped = artifacts.require('$ERC20Capped');
+
+contract('ERC20Capped', function (accounts) {
+  const cap = ether('1000');
+
+  const name = 'My Token';
+  const symbol = 'MTKN';
+
+  it('requires a non-zero cap', async function () {
+    await expectRevert(ERC20Capped.new(name, symbol, 0), 'ERC20Capped: cap is 0');
+  });
+
+  context('once deployed', async function () {
+    beforeEach(async function () {
+      this.token = await ERC20Capped.new(name, symbol, cap);
+    });
+
+    shouldBehaveLikeERC20Capped(accounts, cap);
+  });
+});