diff --git a/active_model_otp.gemspec b/active_model_otp.gemspec
index 0bc9ced..7d2f97d 100644
--- a/active_model_otp.gemspec
+++ b/active_model_otp.gemspec
@@ -22,6 +22,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "rotp"
 
   spec.add_development_dependency "activerecord"
+  spec.add_development_dependency "activemodel-serializers-xml"
   spec.add_development_dependency "bundler", "~> 1.3"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "minitest", "~> 5.4.2"
diff --git a/test/one_time_password_test.rb b/test/one_time_password_test.rb
index a20514b..6f8cfa6 100644
--- a/test/one_time_password_test.rb
+++ b/test/one_time_password_test.rb
@@ -64,31 +64,31 @@ def test_otp_code
 
   def test_otp_code_with_specific_length
     assert_match(/^\d{4}$/, @visitor.otp_code(2160).to_s)
-    assert_operator(@visitor.otp_code(2160).to_s.length, :<= , 4)
+    assert_operator(@visitor.otp_code(2160).to_s.length, :<=, 4)
   end
 
   def test_otp_code_without_specific_length
-   assert_match(/^\d{6}$/, @user.otp_code(2160).to_s)
-   assert_operator(@user.otp_code(2160).to_s.length, :<= , 6)
+    assert_match(/^\d{6}$/, @user.otp_code(2160).to_s)
+    assert_operator(@user.otp_code(2160).to_s.length, :<=, 6)
   end
 
   def test_provisioning_uri_with_provided_account
-    assert_match %r{otpauth://totp/roberto\?secret=\w{16}}, @user.provisioning_uri("roberto")
-    assert_match %r{otpauth://totp/roberto\?secret=\w{16}}, @visitor.provisioning_uri("roberto")
-    assert_match %r{otpauth://hotp/roberto\?secret=\w{16}}, @member.provisioning_uri("roberto")
+    assert_match %r{^otpauth://totp/roberto\?secret=\w{32}$}, @user.provisioning_uri("roberto")
+    assert_match %r{^otpauth://totp/roberto\?secret=\w{32}$}, @visitor.provisioning_uri("roberto")
+    assert_match %r{^otpauth://hotp/roberto\?secret=\w{32}&counter=0$}, @member.provisioning_uri("roberto")
   end
 
   def test_provisioning_uri_with_email_field
-    assert_match %r{otpauth://totp/roberto@heapsource\.com\?secret=\w{16}}, @user.provisioning_uri
-    assert_match %r{otpauth://totp/roberto@heapsource\.com\?secret=\w{16}}, @visitor.provisioning_uri
-    assert_match %r{otpauth://hotp/\?secret=\w{16}&counter=0}, @member.provisioning_uri
+    assert_match %r{^otpauth://totp/roberto@heapsource\.com\?secret=\w{32}$}, @user.provisioning_uri
+    assert_match %r{^otpauth://totp/roberto@heapsource\.com\?secret=\w{32}$}, @visitor.provisioning_uri
+    assert_match %r{^otpauth://hotp/\?secret=\w{32}&counter=0$}, @member.provisioning_uri
   end
 
   def test_provisioning_uri_with_options
-    assert_match %r{otpauth://totp/roberto@heapsource\.com\?secret=\w{16}&issuer=Example}, @user.provisioning_uri(nil, issuer: "Example")
-    assert_match %r{otpauth://totp/roberto@heapsource\.com\?secret=\w{16}&issuer=Example}, @visitor.provisioning_uri(nil, issuer: "Example")
-    assert_match %r{otpauth://totp/roberto\?secret=\w{16}&issuer=Example}, @user.provisioning_uri("roberto", issuer: "Example")
-    assert_match %r{otpauth://totp/roberto\?secret=\w{16}&issuer=Example}, @visitor.provisioning_uri("roberto", issuer: "Example")
+    assert_match %r{^otpauth://totp/Example\:roberto@heapsource\.com\?secret=\w{32}&issuer=Example$}, @user.provisioning_uri(nil, issuer: "Example")
+    assert_match %r{^otpauth://totp/Example\:roberto@heapsource\.com\?secret=\w{32}&issuer=Example$}, @visitor.provisioning_uri(nil, issuer: "Example")
+    assert_match %r{^otpauth://totp/Example\:roberto\?secret=\w{32}&issuer=Example$}, @user.provisioning_uri("roberto", issuer: "Example")
+    assert_match %r{^otpauth://totp/Example\:roberto\?secret=\w{32}&issuer=Example$}, @visitor.provisioning_uri("roberto", issuer: "Example")
   end
 
   def test_regenerate_otp
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 360c4fd..0a4a948 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -9,6 +9,7 @@
 require "minitest/autorun"
 require "minitest/unit"
 require "active_record"
+require "activemodel-serializers-xml"
 
 ActiveRecord::Base.establish_connection adapter: "sqlite3", database: ":memory:"
 load "#{ File.dirname(__FILE__) }/schema.rb"