diff --git a/spec/integration/rails/rails_spec.rb b/spec/integration/rails/rails_spec.rb
index eae1691..723b6c1 100644
--- a/spec/integration/rails/rails_spec.rb
+++ b/spec/integration/rails/rails_spec.rb
@@ -40,7 +40,7 @@
       }
     end
     let(:now) { Time.now }
-    let(:headers) { { 'HTTP_AUTHORIZATION' => 'Basic 123', 'HTTP_X_FORWARDED_FOR' => '5.5.5.5, 1.2.3.4' } }
+    let(:headers) { { 'HTTP_AUTHORIZATION' => 'Basic 123', 'HTTP_X_FORWARDED_FOR' => '5.5.5.5, 1.2.3.4', 'HTTP_CONTENT_LENGTH' => '0' } }
 
     before do
       Timecop.freeze(now)
diff --git a/spec/lib/castle/client_spec.rb b/spec/lib/castle/client_spec.rb
index 25a9b70..0e1bd4a 100644
--- a/spec/lib/castle/client_spec.rb
+++ b/spec/lib/castle/client_spec.rb
@@ -9,7 +9,8 @@
       '/',
       'HTTP_USER_AGENT' => ua,
       'HTTP_X_FORWARDED_FOR' => ip,
-      'HTTP_COOKIE' => "__cid=#{cookie_id};other=efgh"
+      'HTTP_COOKIE' => "__cid=#{cookie_id};other=efgh",
+      'HTTP_CONTENT_LENGTH' => '0'
     )
   end
   let(:request) { Rack::Request.new(env) }
diff --git a/spec/lib/castle/context/get_default_spec.rb b/spec/lib/castle/context/get_default_spec.rb
index fbf0a10..4a48ca2 100644
--- a/spec/lib/castle/context/get_default_spec.rb
+++ b/spec/lib/castle/context/get_default_spec.rb
@@ -12,7 +12,8 @@
       'HTTP_X_FORWARDED_FOR' => ip,
       'HTTP_ACCEPT_LANGUAGE' => 'en',
       'HTTP_USER_AGENT' => 'test',
-      'HTTP_COOKIE' => "__cid=#{client_id};other=efgh"
+      'HTTP_COOKIE' => "__cid=#{client_id};other=efgh",
+      'HTTP_CONTENT_LENGTH' => '0'
     )
   end
   let(:request) { Rack::Request.new(env) }
diff --git a/spec/lib/castle/context/prepare_spec.rb b/spec/lib/castle/context/prepare_spec.rb
index cc6c87b..ed08b2f 100644
--- a/spec/lib/castle/context/prepare_spec.rb
+++ b/spec/lib/castle/context/prepare_spec.rb
@@ -9,7 +9,8 @@
       '/',
       'HTTP_USER_AGENT' => ua,
       'HTTP_X_FORWARDED_FOR' => ip,
-      'HTTP_COOKIE' => "__cid=#{cookie_id};other=efgh"
+      'HTTP_COOKIE' => "__cid=#{cookie_id};other=efgh",
+      'HTTP_CONTENT_LENGTH' => '0'
     )
   end
   let(:request) { Rack::Request.new(env) }
diff --git a/spec/lib/castle/headers/filter_spec.rb b/spec/lib/castle/headers/filter_spec.rb
index 059415b..729ac6b 100644
--- a/spec/lib/castle/headers/filter_spec.rb
+++ b/spec/lib/castle/headers/filter_spec.rb
@@ -14,7 +14,8 @@
         'HTTP_X_FORWARDED_FOR' => '1.2.3.4',
         'HTTP_USER_AGENT' => 'Mozilla 1234',
         'TEST' => '1',
-        'REMOTE_ADDR' => '1.2.3.4'
+        'REMOTE_ADDR' => '1.2.3.4',
+        'HTTP_CONTENT_LENGTH' => '0'
       )
     result[:HTTP_OK] = 'OK'
     result
diff --git a/spec/lib/castle/payload/prepare_spec.rb b/spec/lib/castle/payload/prepare_spec.rb
index f91190a..ff358e3 100644
--- a/spec/lib/castle/payload/prepare_spec.rb
+++ b/spec/lib/castle/payload/prepare_spec.rb
@@ -9,7 +9,8 @@
       '/',
       'HTTP_USER_AGENT' => ua,
       'HTTP_X_FORWARDED_FOR' => ip,
-      'HTTP_COOKIE' => "__cid=#{cookie_id};other=efgh"
+      'HTTP_COOKIE' => "__cid=#{cookie_id};other=efgh",
+      'HTTP_CONTENT_LENGTH' => '0'
     )
   end
   let(:request) { Rack::Request.new(env) }