Merge pull request #2501 from CandleScience/fix-calculator-bug

Fix calculator class check bug

core/app/models/concerns/spree/calculated_adjustments.rb

@@ -32,7 +32,7 @@ def calculator_type
 
     def calculator_type=(calculator_type)
       klass = calculator_type.constantize if calculator_type
-      self.calculator = klass.new if klass && !calculator.is_a?(klass)
+      self.calculator = klass.new if klass && !calculator.instance_of?(klass)
     end
   end
 end

core/spec/lib/calculated_adjustments_spec.rb

@@ -108,4 +108,24 @@
       expect(subject.calculator.preferred_first_item).to eq(123)
     end
   end
+
+  describe '#calculator_type=' do
+    subject { Calculable.new }
+
+    let(:calculator_subclass) { Spree::Calculator::Shipping::FlatRate }
+    let(:calculator_superclass) { Spree::ShippingCalculator }
+
+    before(:each) do
+      subject.calculator_type = calculator_subclass.to_s
+    end
+
+    it 'sets calculator type' do
+      expect(subject.calculator_type).to eq(calculator_subclass.to_s)
+    end
+
+    it 'switches from calculator subclass to calculator superclass' do
+      subject.calculator_type = calculator_superclass.to_s
+      expect(subject.calculator_type).to eq(calculator_superclass.to_s)
+    end
+  end
 end