Fixed erroneous extra line added after blockquote

Added test to make sure extra line is not added.

Author: danielsnider

src/draft-to-markdown.js

@@ -462,8 +462,7 @@ function renderBlock(block, index, rawDraftObject, options) {
     markdownString += '\n';
   } else if (rawDraftObject.blocks[index + 1]) {
     if (rawDraftObject.blocks[index].text) {
-      if (type === 'blockquote' && options.preserveNewlines
-        || SingleNewlineAfterBlock.indexOf(type) !== -1
+      if (SingleNewlineAfterBlock.indexOf(type) !== -1
           && SingleNewlineAfterBlock.indexOf(rawDraftObject.blocks[index + 1].type) === -1) {
         markdownString += '\n\n';
       } else if (!options.preserveNewlines) {

test/idempotency.spec.js

@@ -43,6 +43,13 @@ describe('idempotency', function () {
     expect(markdownFromDraft).toEqual(markdownString);
   });
 
+  it('renders blockquotes correctly', function () {
+    var markdownString = '> Hello I am Blockquote\n\nI am not\n\n> I am';
+    var draftJSObject = markdownToDraft(markdownString, {preserveNewlines: true});
+    var markdownFromDraft = draftToMarkdown(draftJSObject, {preserveNewlines: true});
+    expect(markdownFromDraft).toEqual(markdownString);
+  });
+
   it('renders italic text correctly', function () {
     var markdownString = '_I am italic_ …I am not italic.';
     var draftJSObject = markdownToDraft(markdownString);