Add test

spec/post_spec.rb

@@ -5,6 +5,7 @@
   let(:datestamp) { Time.now.strftime('%Y-%m-%d') }
   let(:filename) { "#{datestamp}-a-test-post.md" }
   let(:path) { posts_dir.join(filename) }
+  let(:jekyll_config) { YAML.load_file('../fixtures/_config.yml') }
 
   before(:all) do
     FileUtils.mkdir_p source_dir unless File.directory? source_dir
@@ -44,6 +45,13 @@
     expect(File.read(path)).to match(/layout: other-layout/)
   end
 
+  it 'creates a new page with the specified config' do
+    expect(Jekyll).to receive(:configuration).and_return(jekyll_config)
+    capture_stdout { described_class.process(args) }
+    expect(File.read(path)).to match(/description: my description/)
+    expect(File.read(path)).to match(/category: /)
+  end
+
   it 'should write a helpful message when successful' do
     output = capture_stdout { described_class.process(args) }
     expect(output).to eql("New post created at _posts/#{filename}.\n")