Test 1:
1. The implementation is in zd_api_client.rb. The corresponding tests to run and test it are in zd_api_client_test.rb

Test 2:
1. The implementation is in css_compressor.rb and the tests are in css_compressor_test.rb. All the css files are in a 
separate folder css_files.

The folder has 3 files to be compressed: 
- multiline.css: This file has lots of blank lines both outside css block and within css block
- multiline_css.css: This file has multiline comments both outside css block and within css block
- simple.css: This is the file given as an example in the problem description

The respective compressed files are multiline_compressed.css, multiline_css_compressed.css, simple_compressed.css.
compressed.css is the expected output file as per problem description and the tests compare against it.

Assumption: I did not remove spaces between the css selector and the open brace or close brace

Test 3:
1. The implementation is in grade.rb and the tests are in grade_test.rb. The tests satisfy the following conditions:

a_plus = Grade.new("A+")
a = Grade.new("A")
a_plus > a => true
[a_plus, a].sort => A, A+

All the code has been tested on ruby 1.9.2 and test-unit 1.2.3 and requires 'rest-client' gem.