Verify configuration exception classes in setter method

lib/service_actor/configurable.rb

@@ -15,6 +15,26 @@ def inherited(child)
       child.failure_class = failure_class || ServiceActor::Failure
     end
 
-    attr_accessor :argument_error_class, :failure_class
+    def argument_error_class=(value)
+      validate_provided_error_class(value)
+
+      @argument_error_class = value
+    end
+
+    def failure_class=(value)
+      validate_provided_error_class(value)
+
+      @failure_class = value
+    end
+
+    attr_reader :argument_error_class, :failure_class
+
+    private
+
+    def validate_provided_error_class(value)
+      return if value.is_a?(Class) && value <= Exception
+
+      raise ArgumentError, "Expected #{value} to be a subclass of Exception"
+    end
   end
 end

spec/actor_spec.rb

@@ -720,6 +720,62 @@
         end
       end
     end
+
+    context "with `failure_class` which is not a class" do
+      let(:actor) do
+        Class.new(Actor) do
+          self.failure_class = 1
+        end
+      end
+
+      it do
+        expect { actor }.to raise_error(
+          ArgumentError, "Expected 1 to be a subclass of Exception"
+        )
+      end
+    end
+
+    context "with `failure_class` that does not inherit `Exception`" do
+      let(:actor) do
+        Class.new(Actor) do
+          self.failure_class = Class.new
+        end
+      end
+
+      it do
+        expect { actor }.to raise_error(
+          ArgumentError, /Expected .+ to be a subclass of Exception/
+        )
+      end
+    end
+
+    context "with `argument_error_class` which is not a class" do
+      let(:actor) do
+        Class.new(Actor) do
+          self.argument_error_class = 1
+        end
+      end
+
+      it do
+        expect { actor }.to raise_error(
+          ArgumentError, "Expected 1 to be a subclass of Exception"
+        )
+      end
+    end
+
+    context "with `argument_error_class` that does not inherit `Exception`" do
+      let(:actor) do
+        Class.new(Actor) do
+          self.argument_error_class = Class.new
+        end
+      end
+
+      it do
+        expect { actor }.to raise_error(
+          ArgumentError, /Expected .+ to be a subclass of Exception/
+        )
+      end
+    end
   end
 
   describe "#result" do