diff --git a/lib/slack-api-wrapper.rb b/lib/slack-api-wrapper.rb
index 1aa0b26..46e7b25 100644
--- a/lib/slack-api-wrapper.rb
+++ b/lib/slack-api-wrapper.rb
@@ -22,6 +22,7 @@ module Slack
   # Parse response. You probably shouldn't be calling this directly.
   # This takes responses from the server and parses them.
   # It also checks for errors and raises exceptions with the appropriate messages.
+  #
   # @param [Net::HTTPResponse] response
   # @param [Boolean] raw if return raw data
   # @raise [SlackError]
diff --git a/lib/slack/request.rb b/lib/slack/request.rb
index 7543281..e887f6b 100644
--- a/lib/slack/request.rb
+++ b/lib/slack/request.rb
@@ -1,18 +1,6 @@
 module Slack
+  # Methods to do http requests
   module Request
-    # Removes nil params
-    #
-    # @param [Hash] params
-    #   API call arguments
-    # @return [Hash]
-    def clean_params(params)
-      r = {}
-      params.each do |k, v|
-        r[k] = v.to_s unless v.nil?
-      end
-      r
-    end
-
     # Convert params to query string
     #
     # @param [Hash] params
@@ -41,5 +29,28 @@ def do_http(uri, request)
         raise Slack::Error, 'SSL error connecting to Slack.'
       end
     end
+
+    def do_http_with_body(uri, request, body) # :nodoc:
+      unless body.nil?
+        if body.is_a?(Hash)
+          request.set_form_data clean_params(body)
+        else
+          s = body.to_s
+          request['Content-Length'] = s.length
+          request.body = s
+        end
+      end
+      do_http(uri, request)
+    end
+
+    private
+
+    def clean_params(params) # :nodoc:
+      r = {}
+      params.each do |k, v|
+        r[k] = v.to_s unless v.nil?
+      end
+      r
+    end
   end
 end
diff --git a/lib/slack/session.rb b/lib/slack/session.rb
index 7ed4358..97e8f18 100644
--- a/lib/slack/session.rb
+++ b/lib/slack/session.rb
@@ -21,19 +21,6 @@ def do_get(path, params = nil) # :nodoc:
       do_http(uri, Net::HTTP::Get.new(uri.request_uri))
     end
 
-    def do_http_with_body(uri, request, body) # :nodoc:
-      unless body.nil?
-        if body.is_a?(Hash)
-          request.set_form_data clean_params(body)
-        else
-          s = body.to_s
-          request['Content-Length'] = s.length
-          request.body = s
-        end
-      end
-      do_http(uri, request)
-    end
-
     def do_post(path, params = nil, headers = nil) # :nodoc:
       headers ||= {}
       headers['Authorization'] = "Bearer #{@access_token}"
diff --git a/slack-api-wrapper.gemspec b/slack-api-wrapper.gemspec
index 7b69609..42a294b 100644
--- a/slack-api-wrapper.gemspec
+++ b/slack-api-wrapper.gemspec
@@ -24,6 +24,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'bundler', '~> 1.7'
   spec.add_development_dependency 'rake', '~> 10.0'
   spec.add_development_dependency 'rspec', '~> 3.2', '>= 3.2.0'
+  spec.add_development_dependency 'webmock', '~> 1.21', '>= 1.21.0'
   spec.add_development_dependency 'coveralls', '~>0.8.0'
   spec.add_development_dependency 'yard', '~> 0.8.7', '>= 0.8.0'
 end
diff --git a/spec/slack/session_spec.rb b/spec/slack/session_spec.rb
index 85367e2..d9195d8 100644
--- a/spec/slack/session_spec.rb
+++ b/spec/slack/session_spec.rb
@@ -11,14 +11,6 @@
 
   describe "instance methods" do
     subject(:session) { Slack::Session.new('') }
-
-    describe '#clean_params' do
-      let(:params) { { 'test_1' => 'test', 'test_2' => nil } }
-      it 'removes nil params' do
-        expect(session.clean_params(params)).to eq('test_1' => 'test')
-      end
-    end
-
     describe '#make_query_string' do
       let(:params) { { 'test_1' => 'test', 'test_2' => 'test' } }
       it 'transform params to query string' do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 7bd47bc..c3b16d0 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -9,6 +9,7 @@
 require 'slack-api-wrapper'
 
 require 'bundler/setup'
+require 'webmock/rspec'
 Bundler.require
 
 RSpec.configure do |config|