Use CLIntegracon for integration specs

spec/integration/xcodeproj_project_yaml.rb

+require "xcodeproj"
+require "yaml"
+
+class Xcodeproj::Project
+  def to_yaml
+    pretty_print_output = pretty_print
+    sections = []
+    sorted_keys = ["File References", "Targets", "Build Configurations"]
+    sorted_keys.each do |key|
+      yaml =  { key => pretty_print_output[key] }.to_yaml
+      sections << yaml
+    end
+    (sections * "\n\n").gsub!("---", '')
+  end
+end