add test for multipart upload empty file

test/_files/empty

@@ -0,0 +1,7 @@
+--AaB03x
+Content-Type: text/plain
+Content-Disposition: attachment; name="files"; filename=empty.txt; modification-date="Wed, 12 Feb 1997 16:29:51 -0500";
+Content-Description: an empty text file
+
+
+--AaB03x--

test/multipart-test.js

@@ -124,6 +124,34 @@ describe('multipart', function () {
       });
     });
 
+    describe('for an empty text file upload', function () {
+      parseFixture('empty');
+
+      it('correctly parses the file name', function () {
+        var file = params.files;
+        assert.ok(file);
+        assert.equal(file.name, 'empty.txt');
+      });
+
+      it('correctly parses the file content type', function () {
+        var file = params.files;
+        assert.ok(file);
+        assert.equal(file.type, 'text/plain');
+      });
+
+      it('correctly determines the file size', function () {
+        var file = params.files;
+        assert.ok(file);
+        assert.strictEqual(file.size, 0);
+      });
+
+      it("correctly parses the file's contents", function () {
+        var file = params.files;
+        assert.ok(file);
+        assert.equal(fs.readFileSync(file.path, 'utf8'), '');
+      });
+    });
+
     describe('for a text file upload using IE-style filename', function () {
       parseFixture('text_ie');