How to pass global variable into one test suite that has 3 test cases

Question

I am trying to verify the delete functionality works as expected, so I am at the same test case creating a post and get its postId then delete it and lastly verify the postId does not found .

    it('deletePost private post for current user',function(done){
      var deleteSamplePost;
      Posts.addPost({postText : 'post for deleting purposes',isPublic : false},(err,resp) =>{
        deleteSamplePost = resp.id;
        console.log('delete',deleteSamplePost);
      Posts.deletePost(deleteSamplePost, (err,r) => {
        expect(err).toEqual(null);
      });
      });
      Posts.getById(deleteSamplePost,(err,re) => {
        expect(err).toEqual('Post not found');
        expect(re).toEqual(undefined);
      });
      done();
    });

I am getting always error variable for getById functionality as 'Post ID is required'. any suggestions?