Add #valid? to PriceChannel

Author: johnnypaper

lib/ruby_technical_analysis/indicators/price_channel.rb

@@ -18,6 +18,11 @@ def call
       calculate_price_channel
     end
 
+    # @return [Boolean] Whether the object is valid
+    def valid?
+      series.length >= period
+    end
+
     private
 
     def _highs

spec/ruby_technical_analysis/indicators/price_channel_spec.rb

@@ -37,6 +37,16 @@ module RubyTechnicalAnalysis
           expect(price_channel.call).to eq([2.974, 2.8127])
         end
       end
+
+      describe "#valid?" do
+        it "returns true if the object is valid" do
+          expect(price_channel.valid?).to eq(true)
+        end
+
+        it "returns false if the object is invalid" do
+          expect(described_class.new(series: []).valid?).to eq(false)
+        end
+      end
     end
 
     describe "secondary series" do