Improve validate_inclusion_of matcher boolean warn messages (#1692)

Closes #1688

The generated warn messages for the validate_inclusion_of matcher do not include
the model/attribute names, which makes it hard to know where
to look at to update/remove the tests.

Following the library's existing warn messages behaviour
of including the attribute in the message, I did the same here.
I believe this is a simple but helpful improvement to help
users fix those warnings. For example: https://github.com/thoughtbot/shoulda-matchers/blob/main/lib/shoulda/matchers/active_model/errors.rb#L17

I did consider adding the line/caller location, but I didn't
find an example of that in the library, and decided to propose
simply adding the model#attribute names.

Author: stefannibrasil

lib/shoulda/matchers/active_model/validate_inclusion_of_matcher.rb

@@ -278,18 +278,6 @@ class ValidateInclusionOfMatcher < ValidationMatcher
         ARBITRARY_OUTSIDE_DATE = Date.jd(9999999)
         ARBITRARY_OUTSIDE_DATETIME = DateTime.jd(9999999)
         ARBITRARY_OUTSIDE_TIME = Time.at(9999999999)
-        BOOLEAN_ALLOWS_BOOLEAN_MESSAGE = <<EOT.freeze
-You are using `validate_inclusion_of` to assert that a boolean column allows
-boolean values and disallows non-boolean ones. Be aware that it is not possible
-to fully test this, as boolean columns will automatically convert non-boolean
-values to boolean ones. Hence, you should consider removing this test.
-EOT
-        BOOLEAN_ALLOWS_NIL_MESSAGE = <<EOT.freeze
-You are using `validate_inclusion_of` to assert that a boolean column allows nil.
-Be aware that it is not possible to fully test this, as anything other than
-true, false or nil will be converted to false. Hence, you should consider
-removing this test.
-EOT
 
         def initialize(attribute)
           super(attribute)
@@ -400,6 +388,24 @@ def does_not_match?(subject)
 
         private
 
+        def boolean_allows_boolean_message
+          <<-EOT.strip
+            You are using `validate_inclusion_of` to assert that the column '#{@subject.class.name}##{attribute}'
+            allows boolean values and disallows non-boolean ones. Be aware that it
+            is not possible to fully test this, as boolean columns will automatically
+            convert non-boolean values to boolean ones. Hence, you should consider
+            removing this test.
+          EOT
+        end
+
+        def boolean_allows_nil_message
+          <<-EOT.strip
+            You are using `validate_inclusion_of` to assert that the column '#{@subject.class.name}##{attribute}'
+            allows nil. Be aware that it is not possible to fully test this, as anything other than
+            true, false or nil will be converted to false. Hence, you should consider removing this test.
+          EOT
+        end
+
         def minimum_range_value
           @range.begin
         end
@@ -492,11 +498,11 @@ def allows_any_value_outside_of_array?
           if attribute_type == :boolean
             case @array
             when [false, true], [true, false]
-              Shoulda::Matchers.warn BOOLEAN_ALLOWS_BOOLEAN_MESSAGE
+              Shoulda::Matchers.warn boolean_allows_boolean_message
               return true
             when [nil]
               if attribute_column.null
-                Shoulda::Matchers.warn BOOLEAN_ALLOWS_NIL_MESSAGE
+                Shoulda::Matchers.warn boolean_allows_nil_message
                 return true
               else
                 raise NonNullableBooleanError.create(@attribute)
@@ -513,11 +519,11 @@ def disallows_all_values_outside_of_array?
           if attribute_type == :boolean
             case @array
             when [false, true], [true, false]
-              Shoulda::Matchers.warn BOOLEAN_ALLOWS_BOOLEAN_MESSAGE
+              Shoulda::Matchers.warn boolean_allows_boolean_message
               return true
             when [nil]
               if attribute_column.null
-                Shoulda::Matchers.warn BOOLEAN_ALLOWS_NIL_MESSAGE
+                Shoulda::Matchers.warn boolean_allows_nil_message
                 return true
               else
                 raise NonNullableBooleanError.create(@attribute)

spec/unit/shoulda/matchers/active_model/validate_inclusion_of_matcher_spec.rb

@@ -690,12 +690,11 @@ def configure_validation_matcher(matcher)
       end
 
       [[false, true], [true, false]].each do |booleans|
-        it 'prints a warning' do
+        it 'prints a warning with the model and attribute names' do
           valid_values = booleans
           builder = build_object_allowing(valid_values)
           message =
-            'You are using `validate_inclusion_of` to assert that a boolean '\
-            'column allows boolean values and disallows non-boolean ones'
+            "You are using `validate_inclusion_of` to assert that the column 'Example#attr' allows boolean values and disallows non-boolean ones"
 
           stderr = capture(:stderr) do
             expect_to_match_in_array(builder, valid_values)
@@ -750,12 +749,11 @@ def validation_matcher_scenario_args
             end
           end
 
-          it 'prints a warning' do
+          it 'prints a warning with the model and attribute names' do
             valid_values = [nil]
             builder = build_object_allowing(valid_values)
             message =
-              'You are using `validate_inclusion_of` to assert that a '\
-              'boolean column allows nil'
+              "You are using `validate_inclusion_of` to assert that the column 'Example#attr' allows nil"
 
             stderr = capture(:stderr) do
               expect_to_match_in_array(builder, valid_values)