content type in elastic tests

spec/elasticsearch.jest.ts

@@ -167,6 +167,9 @@ describe('simple query', function(){
 
   it('check correct time processing', function() {
     let expectedQuery = {
+      headers: {
+        "Content-Type": 'application/json'
+      },
       url: datasourse.url,
       method: 'POST',
       schema: {