Add range tests for numeric with step and mixed arguments

spec/functions/range_spec.rb

@@ -73,5 +73,14 @@
       expected = (1..10).to_a
       expect(scope.function_range([1,10])).to eq expected
     end
+    it "returns a range of numbers with step parameter" do
+      expected = (1..10).step(2).to_a
+      expect(scope.function_range([1,10,2])).to eq expected
+    end
+    it "works with mixed numeric like strings and numeric arguments" do
+      expected = (1..10).to_a
+      expect(scope.function_range(['1',10])).to eq expected
+      expect(scope.function_range([1,'10'])).to eq expected
+    end
   end
 end