Clear some warnings and test against Ruby 2.7

Author: byroot

.rubocop.yml

@@ -2,4 +2,4 @@ inherit_from:
   - https://shopify.github.io/ruby-style-guide/rubocop.yml
 
 AllCops:
-  TargetRubyVersion: 2.6
+  TargetRubyVersion: 2.4

.travis.yml

@@ -3,6 +3,7 @@ language: ruby
 rvm:
   - 2.4
   - 2.6
+  - 2.7
 
 gemfile:
   - gemfiles/Gemfile.rails52

dev.yml

@@ -3,7 +3,10 @@ name: identity-cache
 up:
   - homebrew:
     - postgresql
-  - ruby: 2.4.10
+    - mysql-client@5.7:
+        or:        [mysql@5.7]
+        conflicts: [mysql-connector-c, mysql, mysql-client]
+  - ruby: 2.6.5
   - railgun
   - bundler
 

identity_cache.gemspec

@@ -48,7 +48,7 @@ Gem::Specification.new do |gem|
   else
     gem.add_development_dependency('cityhash', '0.6.0')
     gem.add_development_dependency('mysql2')
-    gem.add_development_dependency('pg', '~> 0.18')
+    gem.add_development_dependency('pg')
     gem.add_development_dependency('stackprof')
   end
 end

test/attribute_cache_test.rb

@@ -80,16 +80,16 @@ def test_cached_attribute_values_are_expired_from_the_cache_when_a_new_record_is
   def test_value_coercion
     assert_queries(1) { assert_equal 'foo', AssociatedRecord.fetch_name_by_id(@record.id.to_f) }
     assert_no_queries { assert_equal 'foo', AssociatedRecord.fetch_name_by_id(@record.id) }
-    @record.update_attributes!(name: 'bar')
+    @record.update!(name: 'bar')
     assert_queries(1) { assert_equal 'bar', AssociatedRecord.fetch_name_by_id(@record.id.to_f) }
   end
 
   def test_no_nil_empty_string_cache_key_conflict
     Item.cache_attribute(:id, by: [:title])
-    @parent.update_attributes!(title: "")
+    @parent.update!(title: "")
     assert_queries(1) { assert_equal @parent.id, Item.fetch_id_by_title("") }
     assert_queries(1) { assert_nil Item.fetch_id_by_title(nil) }
-    @parent.update_attributes!(title: nil)
+    @parent.update!(title: nil)
     assert_queries(1) { assert_nil Item.fetch_id_by_title("") }
     assert_queries(1) { assert_equal @parent.id, Item.fetch_id_by_title(nil) }
   end

test/fetch_multi_test.rb

@@ -270,7 +270,7 @@ def test_fetch_multi_after_expiring_a_record
 
   def test_fetch_multi_id_coercion
     assert_equal(@joe.title, Item.fetch_multi(@joe.id.to_f).first.title)
-    @joe.update_attributes!(title: "#{@joe.title} changed")
+    @joe.update!(title: "#{@joe.title} changed")
 
     assert_equal(@joe.title, Item.fetch_multi(@joe.id.to_f).first.title)
   end

test/lazy_load_associated_classes_test.rb

@@ -28,7 +28,7 @@ def test_cache_invalidation
     assert_queries(0) do
       assert_equal 'baz', Item.fetch(item.id).fetch_associated_records.first.name
     end
-    associated_record.update_attributes!(name: 'buzz')
+    associated_record.update!(name: 'buzz')
     assert_queries(2) do
       assert_equal 'buzz', Item.fetch(item.id).fetch_associated_records.first.name
     end

test/prefetch_associations_test.rb

@@ -80,8 +80,8 @@ def test_prefetch_associations_without_using_cache
 
     def test_prefetch_associations_cached_belongs_to
       Item.send(:cache_belongs_to, :item)
-      @bob.update_attributes!(item_id: @joe.id)
-      @joe.update_attributes!(item_id: @fred.id)
+      @bob.update!(item_id: @joe.id)
+      @joe.update!(item_id: @fred.id)
       @bob.fetch_item
       @joe.fetch_item
       items = [@bob, @joe].map(&:reload)
@@ -101,8 +101,8 @@ def test_prefetch_associations_cached_belongs_to
 
     def test_prefetch_associations_notifies_about_hydration
       Item.send(:cache_belongs_to, :item)
-      @bob.update_attributes!(item_id: @joe.id)
-      @joe.update_attributes!(item_id: @fred.id)
+      @bob.update!(item_id: @joe.id)
+      @joe.update!(item_id: @fred.id)
       @bob.fetch_item
       @joe.fetch_item
       items = [@bob, @joe].map(&:reload)
@@ -119,7 +119,7 @@ def test_prefetch_associations_notifies_about_hydration
 
     def test_prefetch_associations_with_nil_cached_belongs_to
       Item.send(:cache_belongs_to, :item)
-      @bob.update_attributes!(item_id: 1234)
+      @bob.update!(item_id: 1234)
       assert_nil(@bob.fetch_item)
 
       assert_no_queries do