fix(assets): can now use multiple assets in the same stack (#725)

Fixed by attaching the imported bucket to the Asset object instead
of the Asset object's parent.

Fixes #706.

packages/@aws-cdk/assets/lib/asset.ts

@@ -99,7 +99,7 @@ export class Asset extends cdk.Construct {
         const s3Filename = new cdk.FnSelect(1, new cdk.FnSplit(cxapi.ASSET_PREFIX_SEPARATOR, keyParam.value));
         this.s3ObjectKey = new s3.ObjectKey(new cdk.FnConcat(this.s3Prefix, s3Filename));
 
-        this.bucket = s3.BucketRef.import(parent, 'AssetBucket', {
+        this.bucket = s3.BucketRef.import(this, 'AssetBucket', {
             bucketName: this.s3BucketName
         });
 

packages/@aws-cdk/assets/test/test.asset.ts

@@ -98,5 +98,18 @@ export = {
             path: '/path/not/found/' + Math.random() * 999999
         }));
         test.done();
-    }
+    },
+
+    'multiple assets under the same parent'(test: Test) {
+        // GIVEN
+        const stack = new cdk.Stack();
+
+        // WHEN
+        new ZipDirectoryAsset(stack, 'MyDirectory1', { path: '.' });
+        new ZipDirectoryAsset(stack, 'MyDirectory2', { path: '.' });
+
+        // THEN: no error
+
+        test.done();
+    },
 };