Review some tests from AMo::Errors to remove "should" usage

Also remove duplicated tests for Errors#as_json and minor improvements
in some tests.

activemodel/test/cases/errors_test.rb

@@ -54,7 +54,7 @@ def test_has_key?
     assert errors.has_key?(:foo), 'errors should have key :foo'
   end
 
-  test "should be able to clear the errors" do
+  test "clear errors" do
     person = Person.new
     person.validate!
 
@@ -63,7 +63,7 @@ def test_has_key?
     assert person.errors.empty?
   end
 
-  test "get returns the error by the provided key" do
+  test "get returns the errors for the provided key" do
     errors = ActiveModel::Errors.new(self)
     errors[:foo] = "omg"
 
@@ -93,182 +93,162 @@ def test_has_key?
     assert_equal [:foo, :baz], errors.keys
   end
 
-  test "as_json returns a json formatted representation of the errors hash" do
-    person = Person.new
-    person.validate!
-
-    assert_equal({ name: ["can not be nil"] }, person.errors.as_json)
-  end
-
-  test "as_json with :full_messages option" do
-    person = Person.new
-    person.validate!
-
-    assert_equal({ name: ["name can not be nil"] }, person.errors.as_json(full_messages: true))
-  end
-
-  test "should return true if no errors" do
+  test "detecting whether there are errors with empty?, blank?, include?" do
     person = Person.new
     person.errors[:foo]
     assert person.errors.empty?
     assert person.errors.blank?
     assert !person.errors.include?(:foo)
   end
 
-  test "method validate! should work" do
+  test "adding errors using conditionals with Person#validate!" do
     person = Person.new
     person.validate!
     assert_equal ["name can not be nil"], person.errors.full_messages
     assert_equal ["can not be nil"], person.errors[:name]
   end
 
-  test 'should be able to assign error' do
+  test "assign error" do
     person = Person.new
     person.errors[:name] = 'should not be nil'
     assert_equal ["should not be nil"], person.errors[:name]
   end
 
-  test 'should be able to add an error on an attribute' do
+  test "add an error message on a specific attribute" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     assert_equal ["can not be blank"], person.errors[:name]
   end
 
-  test "should be able to add an error with a symbol" do
+  test "add an error with a symbol" do
     person = Person.new
     person.errors.add(:name, :blank)
     message = person.errors.generate_message(:name, :blank)
     assert_equal [message], person.errors[:name]
   end
 
-  test "should be able to add an error with a proc" do
+  test "add an error with a proc" do
     person = Person.new
     message = Proc.new { "can not be blank" }
     person.errors.add(:name, message)
     assert_equal ["can not be blank"], person.errors[:name]
   end
 
-  test "added? should be true if that error was added" do
+  test "added? detects if a specific error was added to the object" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     assert person.errors.added?(:name, "can not be blank")
   end
 
-  test "added? should handle when message is a symbol" do
+  test "added? handles symbol message" do
     person = Person.new
     person.errors.add(:name, :blank)
     assert person.errors.added?(:name, :blank)
   end
 
-  test "added? should handle when message is a proc" do
+  test "added? handles proc messages" do
     person = Person.new
     message = Proc.new { "can not be blank" }
     person.errors.add(:name, message)
     assert person.errors.added?(:name, message)
   end
 
-  test "added? should default message to :invalid" do
+  test "added? defaults message to :invalid" do
     person = Person.new
     person.errors.add(:name)
     assert person.errors.added?(:name)
   end
 
-  test "added? should be true when several errors are present, and we ask for one of them" do
+  test "added? matches the given message when several errors are present for the same attribute" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     person.errors.add(:name, "is invalid")
     assert person.errors.added?(:name, "can not be blank")
   end
 
-  test "added? should be false if no errors are present" do
+  test "added? returns false when no errors are present" do
     person = Person.new
     assert !person.errors.added?(:name)
   end
 
-  test "added? should be false when an error is present, but we check for another error" do
+  test "added? returns false when checking a nonexisting error and other errors are present for the given attribute" do
     person = Person.new
     person.errors.add(:name, "is invalid")
     assert !person.errors.added?(:name, "can not be blank")
   end
 
-  test 'should respond to size' do
+  test "size calculates the number of error messages" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     assert_equal 1, person.errors.size
   end
 
-  test 'to_a should return an array' do
+  test "to_a returns the list of errors with complete messages containing the attribute names" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     person.errors.add(:name, "can not be nil")
     assert_equal ["name can not be blank", "name can not be nil"], person.errors.to_a
   end
 
-  test 'to_hash should return a hash' do
+  test "to_hash returns the error messages hash" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
-    assert_instance_of ::Hash, person.errors.to_hash
+    assert_equal({ name: ["can not be blank"] }, person.errors.to_hash)
   end
 
-  test 'full_messages should return an array of error messages, with the attribute name included' do
+  test "full_messages creates a list of error messages with the attribute name included" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     person.errors.add(:name, "can not be nil")
     assert_equal ["name can not be blank", "name can not be nil"], person.errors.full_messages
   end
-  
-  test 'full_messages_for should contain all the messages for a given attribute' do
+
+  test "full_messages_for contains all the error messages for the given attribute" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     person.errors.add(:name, "can not be nil")
     assert_equal ["name can not be blank", "name can not be nil"], person.errors.full_messages_for(:name)
   end
 
-  test 'full_messages_for should not contain messages for another attributes' do
+  test "full_messages_for does not contain error messages from other attributes" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     person.errors.add(:email, "can not be blank")
     assert_equal ["name can not be blank"], person.errors.full_messages_for(:name)
   end
 
-  test "full_messages_for should return an empty array in case if errors hash doesn't contain a given attribute" do
+  test "full_messages_for returns an empty list in case there are no errors for the given attribute" do
     person = Person.new
     person.errors.add(:name, "can not be blank")
     assert_equal [], person.errors.full_messages_for(:email)
   end
 
-  test 'full_message should return the given message if attribute equals :base' do
+  test "full_message returns the given message when attribute is :base" do
     person = Person.new
     assert_equal "press the button", person.errors.full_message(:base, "press the button")
   end
 
-  test 'full_message should return the given message with the attribute name included' do
+  test "full_message returns the given message with the attribute name included" do
     person = Person.new
     assert_equal "name can not be blank", person.errors.full_message(:name, "can not be blank")
     assert_equal "name_test can not be blank", person.errors.full_message(:name_test, "can not be blank")
   end
 
-  test 'should return a JSON hash representation of the errors' do
+  test "as_json creates a json formatted representation of the errors hash" do
     person = Person.new
-    person.errors.add(:name, "can not be blank")
-    person.errors.add(:name, "can not be nil")
-    person.errors.add(:email, "is invalid")
-    hash = person.errors.as_json
-    assert_equal ["can not be blank", "can not be nil"], hash[:name]
-    assert_equal ["is invalid"], hash[:email]
+    person.validate!
+
+    assert_equal({ name: ["can not be nil"] }, person.errors.as_json)
   end
 
-  test 'should return a JSON hash representation of the errors with full messages' do
+  test "as_json with :full_messages option creates a json formatted representation of the errors containing complete messages" do
     person = Person.new
-    person.errors.add(:name, "can not be blank")
-    person.errors.add(:name, "can not be nil")
-    person.errors.add(:email, "is invalid")
-    hash = person.errors.as_json(:full_messages => true)
-    assert_equal ["name can not be blank", "name can not be nil"], hash[:name]
-    assert_equal ["email is invalid"], hash[:email]
+    person.validate!
+
+    assert_equal({ name: ["name can not be nil"] }, person.errors.as_json(full_messages: true))
   end
 
-  test "generate_message should work without i18n_scope" do
+  test "generate_message works without i18n_scope" do
     person = Person.new
     assert !Person.respond_to?(:i18n_scope)
     assert_nothing_raised {