Add support for scopes

lib/time_for_a_boolean.rb

@@ -6,7 +6,7 @@
 require "time_for_a_boolean/railtie"
 
 module TimeForABoolean
-  def time_for_a_boolean(attribute, field=:"#{attribute}_at")
+  def time_for_a_boolean(attribute, field=:"#{attribute}_at", scope: false)
     define_method(attribute) do
       !send(field).nil? && send(field) <= -> { Time.current }.()
     end
@@ -25,5 +25,13 @@ def time_for_a_boolean(attribute, field=:"#{attribute}_at")
     define_method(:"#{attribute}!") do
       send(:"#{attribute}=", true)
     end
+
+    if scope && respond_to?(:where)
+      singleton_class.instance_eval do
+        define_method(:"#{attribute}") do
+          where.not("#{field}": nil)
+        end
+      end
+    end
   end
 end

spec/time_for_a_boolean_spec.rb

@@ -153,12 +153,40 @@
     end
   end
 
+  describe 'scope' do
+    it 'does not define the scope by default' do
+      klass.time_for_a_boolean :attribute
+
+      expect(klass).not_to respond_to :attribute
+    end
+
+    it 'does not define the scope if the class does not respond to where' do
+      klass.time_for_a_boolean :attribute, scope: true
+
+      expect(klass).not_to respond_to :attribute
+    end
+
+    it 'defines the scope if the class has a where method' do
+      klass_with_where.time_for_a_boolean :attribute, scope: true
+
+      expect(klass_with_where).to respond_to :attribute
+    end
+  end
   def klass
     @klass ||= Class.new do
       extend TimeForABoolean
     end
   end
 
+  def klass_with_where
+    @klass ||= Class.new do
+      extend TimeForABoolean
+
+      def self.where(...)
+      end
+    end
+  end
+
   def object
     @object ||= klass.new
   end