Use client header spec as per documentation

.bundle/config

@@ -1,2 +1,3 @@
 ---
-BUNDLE_JOBS: 4
+BUNDLE_JOBS: '4'
+BUNDLE_BIN: bin

lib/auth0/mixins/initializer.rb

@@ -29,12 +29,18 @@ def self.included(klass)
       private
 
       def client_headers(config)
-        sdk_headers = {
-          'Content-Type' => 'application/json',
+        client_info = JSON.dump({name: 'ruby-auth0', version: Auth0::VERSION})
+
+        headers = {
+          'Content-Type' => 'application/json'
         }
-        sdk_headers['User-Agent'] = "Ruby/#{RUBY_VERSION}" if not config[:opt_out_sdk_info]
-        sdk_headers['Auth0-Client'] = "ruby-auth0/#{Auth0::VERSION}" if not config[:opt_out_sdk_info]
-        sdk_headers
+
+        if !config[:opt_out_sdk_info]
+          headers['User-Agent'] = "Ruby/#{RUBY_VERSION}"
+          headers['Auth0-Client'] = Base64.urlsafe_encode64(client_info)
+        end
+
+        headers
       end
 
       def api_domain(options)

spec/integration/lib/auth0/auth0_client_spec.rb

@@ -42,15 +42,32 @@
     let(:credentials) { v2_credentials.merge({access_token: ENV["MASTER_JWT"]}) }
   end
 
-  describe "client headers" do
-    let(:access_token) { 'abc123' }
-    let(:domain) { 'myhost.auth0.com' }
-    let(:client) { Auth0::Client.new(v2_credentials.merge({access_token: access_token, domain: domain})) }
-
+  context "client headers" do
+    let(:client) { Auth0::Client.new(v2_credentials.merge({access_token: 'abc123', domain: 'myhost.auth0.com'})) }
     let(:headers) { client.class.headers }
-    specify { expect(headers).to include("Auth0-Client" => "ruby-auth0/#{Auth0::VERSION}") }
-    specify { expect(headers).to include("User-Agent" => "Ruby/#{RUBY_VERSION}") }
-    specify { expect(headers).to include("Authorization" => "Bearer #{access_token}") }
-    specify { expect(headers).to include("Content-Type" => "application/json") }
+
+    let(:base64_token) {
+      Base64.urlsafe_encode64('{"name":"ruby-auth0","version":"'+Auth0::VERSION+'"}')
+    }
+
+    it "has the correct headers present" do
+      expect(headers.keys.sort).to eql ['Auth0-Client', 'Authorization', 'Content-Type', 'User-Agent']
+    end
+
+    it "uses the correct access token" do
+      expect(headers['Authorization']).to eql "Bearer abc123"
+    end
+
+    it "is always json" do
+      expect(headers['Content-Type']).to eql 'application/json'
+    end
+
+    it "sets the ruby version" do
+      expect(headers['User-Agent']).to eql "Ruby/#{RUBY_VERSION}"
+    end
+
+    it "sets the client version" do
+      expect(headers['Auth0-Client']).to eql base64_token
+    end
   end
 end

spec/lib/auth0/mixins/initializer_spec.rb

@@ -1,29 +1,29 @@
 require "spec_helper"
 
 class MockClass
-  attr_reader :token 
+  attr_reader :token
   include Auth0::Mixins::Initializer
   include HTTParty
 end
 
 describe Auth0::Mixins::Initializer do
   let(:params) { { namespace: 'samples.auth0.com' } }
-  let(:instance) { DummyClassForProxy.include(described_class).new(params) }
+  let(:instance) { DummyClassForProxy.send(:include, described_class).new(params) }
   context 'api v2' do
     before do
       params[:api_version] = 2
     end
-    
+
     it 'sets token when access_token is passed' do
       params[:access_token] = '123'
-      
+
       expect(instance.instance_variable_get('@token')).to eq('123')
     end
 
     it 'sets token when token is passed' do
       params[:token] = '123'
-      
-      expect(instance.instance_variable_get('@token')).to eq('123')  
+
+      expect(instance.instance_variable_get('@token')).to eq('123')
     end
   end
 end