diff --git a/.travis.yml b/.travis.yml
index 78b19dd8..0aaa2fbb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,6 @@ language: ruby
 
 # Specify which ruby versions you wish to run your tests on, each version will be used
 rvm:
-  - 2.0.0
   - 2.1
   - 2.2
   - 2.3
diff --git a/lib/json/add/complex.rb b/lib/json/add/complex.rb
index 4d977e75..e63e29fd 100644
--- a/lib/json/add/complex.rb
+++ b/lib/json/add/complex.rb
@@ -2,7 +2,6 @@
 unless defined?(::JSON::JSON_LOADED) and ::JSON::JSON_LOADED
   require 'json'
 end
-defined?(::Complex) or require 'complex'
 
 class Complex
 
diff --git a/lib/json/add/rational.rb b/lib/json/add/rational.rb
index 6be40345..f7762260 100644
--- a/lib/json/add/rational.rb
+++ b/lib/json/add/rational.rb
@@ -2,7 +2,6 @@
 unless defined?(::JSON::JSON_LOADED) and ::JSON::JSON_LOADED
   require 'json'
 end
-defined?(::Rational) or require 'rational'
 
 class Rational
   # Deserializes JSON string by converting numerator value <tt>n</tt>,
diff --git a/tests/json_common_interface_test.rb b/tests/json_common_interface_test.rb
index 4fdc2b11..9148b78c 100644
--- a/tests/json_common_interface_test.rb
+++ b/tests/json_common_interface_test.rb
@@ -152,31 +152,18 @@ def test_load_file_with_option_shared(method_name)
     temp_file_containing(@json) do |filespec|
       parsed_object = JSON.public_send(method_name, filespec, symbolize_names: true)
       key_classes = parsed_object.keys.map(&:class)
-      assert_true key_classes.include?(Symbol) && (! key_classes.include?(String))
+      assert_include(key_classes, Symbol)
+      assert_not_include(key_classes, String)
     end
   end
 
-  # Copied and slightly modified from https://github.com/keithrbennett/trick_bag
-  # (https://github.com/keithrbennett/trick_bag/blob/master/lib/trick_bag/io/temp_files.rb).
-  #
-  # For the easy creation and deletion of a temp file populated with text,
-  # wrapped around the code block you provide.
-  #
-  # @param text the text to write to the temporary file
-  # @param file_prefix optional prefix for the temporary file's name
-  # @yield filespec of the temporary file
   def temp_file_containing(text, file_prefix = '')
     raise "This method must be called with a code block." unless block_given?
 
-    filespec = nil
-    begin
-      Tempfile.open(file_prefix) do |file|
-        file << text
-        filespec = file.path
-      end
-      yield(filespec)
-    ensure
-      File.delete(filespec) if filespec && File.exist?(filespec)
-    end
+    Tempfile.create(file_prefix) do |file|
+      file << text
+      file.close
+      yield file.path
     end
+  end
 end
diff --git a/tests/json_generator_test.rb b/tests/json_generator_test.rb
old mode 100755
new mode 100644
diff --git a/tests/json_parser_test.rb b/tests/json_parser_test.rb
index e29f3f12..dce693e5 100644
--- a/tests/json_parser_test.rb
+++ b/tests/json_parser_test.rb
@@ -222,10 +222,10 @@ def test_freeze
     assert_predicate parse('{}', :freeze => true), :frozen?
     assert_predicate parse('[]', :freeze => true), :frozen?
     assert_predicate parse('"foo"', :freeze => true), :frozen?
-    
+
     if string_deduplication_available?
-      assert_same -'foo', parse('"foo"', :freeze => true)
-      assert_same -'foo', parse('{"foo": 1}', :freeze => true).keys.first
+      assert_same(-'foo', parse('"foo"', :freeze => true))
+      assert_same(-'foo', parse('{"foo": 1}', :freeze => true).keys.first)
     end
   end