fix: made all the tests consistent. now with done.

test/Ownable.js

@@ -1,35 +1,40 @@
 contract('Ownable', function(accounts) {
-  var ownable;
+  let ownable;
 
-  beforeEach(async function() {
+  beforeEach(async function(done) {
     ownable = await Ownable.new();
+    done();
   });
 
-  it("should have an owner", async function() {
+  it("should have an owner", async function(done) {
     let owner = await ownable.owner();
     assert.isTrue(owner != 0);
+    done();
   });
 
-  it("changes owner after transfer", async function() {
+  it("changes owner after transfer", async function(done) {
     let other = accounts[1];
     let transfer = await ownable.transfer(other);
     let owner = await ownable.owner();
     assert.isTrue(owner === other);
+    done();
   });
 
-  it("should prevent non-owners from transfering", async function() {
+  it("should prevent non-owners from transfering", async function(done) {
     let other = accounts[2];
     let transfer = await ownable.transfer(other, {from: accounts[2]});
     let owner = await ownable.owner();
      assert.isFalse(owner === other);
+     done();
   });
 
-  it("should guard ownership against stuck state", async function() {
+  it("should guard ownership against stuck state", async function(done) {
     let ownable = Ownable.deployed();
     let originalOwner = await ownable.owner();
     let transfer = await ownable.transfer(null, {from: originalOwner});
     let newOwner = await ownable.owner();
     assert.equal(originalOwner, newOwner);
+    done();
   });
 
 });