diff --git a/Appraisals b/Appraisals
index f0495db..2ccb781 100644
--- a/Appraisals
+++ b/Appraisals
@@ -4,6 +4,10 @@ end
 
 appraise "rack_1_6" do
   gem "rack", "~> 1.6.9"
+
+  # Override rack-test version constraint by making it more loose
+  # so it's compatible with actionpack 4.2.x
+  gem "rack-test", ">= 0.6"
 end
 
 appraise 'rails_5-2' do
@@ -19,6 +23,10 @@ end
 appraise 'rails_4-2' do
   gem 'actionpack', '~> 4.2.0'
   gem 'activesupport', '~> 4.2.0'
+
+  # Override rack-test version constraint by making it more loose
+  # so it's compatible with actionpack 4.2.x
+  gem "rack-test", ">= 0.6"
 end
 
 appraise 'dalli2' do
diff --git a/gemfiles/rack_1_6.gemfile b/gemfiles/rack_1_6.gemfile
index 18b3acf..8b636ed 100644
--- a/gemfiles/rack_1_6.gemfile
+++ b/gemfiles/rack_1_6.gemfile
@@ -3,5 +3,6 @@
 source "https://rubygems.org"
 
 gem "rack", "~> 1.6.9"
+gem "rack-test", ">= 0.6"
 
 gemspec path: "../"
diff --git a/gemfiles/rails_4_2.gemfile b/gemfiles/rails_4_2.gemfile
index 3937ece..eb09083 100644
--- a/gemfiles/rails_4_2.gemfile
+++ b/gemfiles/rails_4_2.gemfile
@@ -4,5 +4,6 @@ source "https://rubygems.org"
 
 gem "actionpack", "~> 4.2.0"
 gem "activesupport", "~> 4.2.0"
+gem "rack-test", ">= 0.6"
 
 gemspec path: "../"