Added: RSpec test suite initial setup.

.rspec

@@ -0,0 +1 @@
+--require spec_helper

ddtrace.gemspec

@@ -35,7 +35,9 @@ EOS
   spec.add_dependency 'msgpack'
 
   spec.add_development_dependency 'rake', '~> 10.5'
-  spec.add_development_dependency('rubocop', '= 0.49.1') if RUBY_VERSION >= '2.1.0'
+  spec.add_development_dependency 'rubocop', '= 0.49.1' if RUBY_VERSION >= '2.1.0'
+  spec.add_development_dependency 'rspec', '~> 3.0'
+  spec.add_development_dependency 'rspec-collection_matchers', '~> 1.1'
   spec.add_development_dependency 'minitest', '= 5.10.1'
   spec.add_development_dependency 'appraisal', '~> 2.2'
   spec.add_development_dependency 'yard', '~> 0.9'

spec/spec_helper.rb

@@ -0,0 +1,20 @@
+$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
+require 'pry'
+require 'rspec/collection_matchers'
+
+require 'ddtrace'
+
+RSpec.configure do |config|
+  config.expect_with :rspec do |expectations|
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  config.mock_with :rspec do |mocks|
+    mocks.verify_partial_doubles = true
+  end
+
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+  config.disable_monkey_patching!
+  config.warnings = true
+  config.order = :random
+end