ERC721 pausable token (#1154)

* ERC721 pausable token

* Reuse of ERC721 Basic behavior for Pausable, split view checks in paused state & style fixes

* [~] paused token behavior

test/token/ERC721/ERC721PausableToken.test.js

@@ -0,0 +1,36 @@
+const { shouldBehaveLikeERC721PausedToken } = require('./ERC721PausedToken.behavior');
+const { shouldBehaveLikeERC721BasicToken } = require('./ERC721BasicToken.behavior');
+
+const BigNumber = web3.BigNumber;
+const ERC721PausableToken = artifacts.require('ERC721PausableTokenMock.sol');
+
+require('chai')
+  .use(require('chai-bignumber')(BigNumber))
+  .should();
+
+contract('ERC721PausableToken', function ([_, owner, recipient, operator, ...otherAccounts]) {
+  beforeEach(async function () {
+    this.token = await ERC721PausableToken.new({ from: owner });
+  });
+
+  context('when token is paused', function () {
+    beforeEach(async function () {
+      await this.token.pause({ from: owner });
+    });
+
+    shouldBehaveLikeERC721PausedToken(owner, [...otherAccounts]);
+  });
+
+  context('when token is not paused yet', function () {
+    shouldBehaveLikeERC721BasicToken([owner, ...otherAccounts]);
+  });
+
+  context('when token is paused and then unpaused', function () {
+    beforeEach(async function () {
+      await this.token.pause({ from: owner });
+      await this.token.unpause({ from: owner });
+    });
+
+    shouldBehaveLikeERC721BasicToken([owner, ...otherAccounts]);
+  });
+});