Fix the undefined method error for non rails project due to use of many? method. (#1459)

* Fix the undefined method error for non rails project due to use of many? method

* Add tests for inclusion validation for non rails app.

* Remove unnecessary spaces.

* Rubocop offenses.

Co-authored-by: Nitin S <nitin.singh@edcast.com>
Co-authored-by: = <=>

lib/shoulda/matchers/active_model/validate_inclusion_of_matcher.rb

@@ -355,7 +355,7 @@ EOT
             description = "validate that :#{@attribute}"
 
             description <<
-              if @array.many?
+              if @array.count > 1
                 " is either #{inspected_array}"
               else
                 " is #{inspected_array}"

spec/acceptance/active_model_integration_spec.rb

@@ -1,13 +1,34 @@
 require 'acceptance_spec_helper'
 
 describe 'shoulda-matchers integrates with an ActiveModel project' do
-  specify 'and loads without errors' do
+  before do
     create_active_model_project
 
-    add_shoulda_matchers_to_project(
-      test_frameworks: [:rspec],
-      libraries: [:active_model],
-    )
+    write_file 'lib/user.rb', <<-FILE
+      require 'active_model'
+
+      class User
+        include ActiveModel::Validations
+        attr_accessor :gender
+
+        validates :gender, inclusion: { in: %w(male female) }
+      end
+    FILE
+
+    write_file 'spec/user_spec.rb', <<-FILE
+      require 'spec_helper'
+      require 'user'
+      include Shoulda::Matchers::ActiveModel
+
+      describe User do
+        context 'when gender is valid' do
+          it { is_expected.to validate_inclusion_of(:gender).in_array(%w(male female)) }
+        end
+        context 'when gender is invalid' do
+          it { is_expected.to validate_inclusion_of(:gender).in_array(%w(transgender female)) }
+        end
+      end
+    FILE
 
     write_file 'load_dependencies.rb', <<-FILE
       require 'active_model'
@@ -17,7 +38,42 @@ describe 'shoulda-matchers integrates with an ActiveModel project' do
       puts "Loaded all dependencies without errors"
     FILE
 
-    result = run_command_within_bundle('ruby load_dependencies.rb')
-    expect(result).to have_output('Loaded all dependencies without errors')
+    updating_bundle do
+      add_rspec_to_project
+      add_shoulda_matchers_to_project(
+        manually: true,
+        with_configuration: false,
+      )
+
+      write_file 'spec/spec_helper.rb', <<-FILE
+        require 'active_model'
+        require 'shoulda-matchers'
+
+        Shoulda::Matchers.configure do |config|
+          config.integrate do |with|
+            with.test_framework :rspec
+
+            with.library :active_model
+          end
+        end
+      FILE
+    end
+  end
+
+  context 'when using active model library' do
+    it 'and loads without errors' do
+      result = run_command_within_bundle('ruby load_dependencies.rb')
+
+      expect(result).to have_output('Loaded all dependencies without errors')
+    end
+
+    it 'allows use of inclusion matcher from active model library' do
+      result = run_rspec_tests('spec/user_spec.rb')
+
+      expect(result).to have_output('2 examples, 1 failure')
+      expect(result).to have_output(
+        'gender: ["is not included in the list"]',
+      )
+    end
   end
 end