Add ReentrancyGuard

test/ReentrancyGuard.js

@@ -0,0 +1,31 @@
+'use strict';
+import expectThrow from './helpers/expectThrow';
+const ReentrancyMock = artifacts.require('./helper/ReentrancyMock.sol');
+const ReentrancyAttack = artifacts.require('./helper/ReentrancyAttack.sol');
+
+contract('ReentrancyGuard', function(accounts) {
+  let reentrancyMock;
+
+  beforeEach(async function() {
+    reentrancyMock = await ReentrancyMock.new();
+    let initialCounter = await reentrancyMock.counter();
+    assert.equal(initialCounter, 0);
+  });
+
+  it('should not allow remote callback', async function() {
+    let attacker = await ReentrancyAttack.new();
+    await expectThrow(reentrancyMock.countAndCall(attacker.address));
+  });
+
+  // The following are more side-effects that intended behaviour:
+  // I put them here as documentation, and to monitor any changes
+  // in the side-effects.
+
+  it('should not allow local recursion', async function() {
+    await expectThrow(reentrancyMock.countLocalRecursive(10));
+  });
+
+  it('should not allow indirect local recursion', async function() {
+    await expectThrow(reentrancyMock.countThisRecursive(10));
+  });
+});