bump Rails, and fixes for Rails 5.1.4

Appraisals

@@ -1,11 +1,11 @@
 appraise "rails-3" do
-  gem "rails", "3.2.22.4"
+  gem "rails", "3.2.22.5"
 end
 
 appraise "rails-4" do
-  gem "rails", "4.2.7.1"
+  gem "rails", "4.2.10"
 end
 
 appraise "rails-5" do
-  gem "rails", "5.0.0.1"
+  gem "rails", "5.1.4"
 end

acts_as_textcaptcha.gemspec

@@ -31,7 +31,7 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib"]
 
   # always test against latest rails version
-  s.add_development_dependency('rails', '~> 5.0.0.1')
+  s.add_development_dependency('rails', '~> 5.1.4')
 
   s.add_development_dependency('mime-types')
   s.add_development_dependency('bundler')

test/textcaptcha_api_test.rb

@@ -30,17 +30,17 @@
       URI::InvalidURIError
     ].each do |error|
        stub_request(:get, "http://textcaptcha.com/api/xyz").to_raise(error)
-       ActsAsTextcaptcha::TextcaptchaApi.fetch('xyz').must_equal nil
+       assert_nil ActsAsTextcaptcha::TextcaptchaApi.fetch('xyz')
      end
   end
 
   it 'should return nil when body cannot be parsed as XML' do
     stub_request(:get, "http://textcaptcha.com/api/jibber").to_return(:body => 'here be gibberish')
-    ActsAsTextcaptcha::TextcaptchaApi.fetch('jibber').must_equal nil
+    assert_nil ActsAsTextcaptcha::TextcaptchaApi.fetch('jibber')
   end
 
   it 'should return nil when body is empty' do
     stub_request(:get, "http://textcaptcha.com/api/empty").to_return(:body => '')
-    ActsAsTextcaptcha::TextcaptchaApi.fetch('empty').must_equal nil
+    assert_nil ActsAsTextcaptcha::TextcaptchaApi.fetch('empty')
   end
 end

test/textcaptcha_cache_test.rb

@@ -20,6 +20,6 @@
     @cache.read('mykey').must_equal [1,2,3]
     @cache.delete('mykey')
 
-    @cache.read('mykey').must_equal nil
+    assert_nil @cache.read('mykey')
   end
 end

test/textcaptcha_test.rb

@@ -131,17 +131,17 @@
 
       stub_request(:get, %r{http://textcaptcha.com/api/}).to_raise(SocketError)
       @comment.textcaptcha
-      @comment.textcaptcha_question.must_equal nil
-      @comment.textcaptcha_key.must_equal nil
+      assert_nil @comment.textcaptcha_question
+      assert_nil @comment.textcaptcha_key
     end
 
     it 'should not generate any question or answer when user defined questions set incorrectly' do
       @comment = MovieReview.new
 
       stub_request(:get, %r{http://textcaptcha.com/api/}).to_raise(SocketError)
       @comment.textcaptcha
-      @comment.textcaptcha_question.must_equal nil
-      @comment.textcaptcha_key.must_equal nil
+      assert_nil @comment.textcaptcha_question
+      assert_nil @comment.textcaptcha_key
     end
   end