Stub the single item array method

Author: kpaulisse

lib/octocatalog-diff/catalog-diff/filter.rb

@@ -2,6 +2,7 @@
 require_relative 'filter/absent_file'
 require_relative 'filter/compilation_dir'
 require_relative 'filter/json'
+require_relative 'filter/single_item_array'
 require_relative 'filter/yaml'
 
 require 'stringio'
@@ -13,7 +14,7 @@ class Filter
       attr_accessor :logger
 
       # List the available filters here (by class name) for use in the validator method.
-      AVAILABLE_FILTERS = %w(AbsentFile CompilationDir JSON YAML).freeze
+      AVAILABLE_FILTERS = %w(AbsentFile CompilationDir JSON SingleItemArray YAML).freeze
 
       # Public: Determine whether a particular filter exists. This can be used to validate
       # a user-submitted filter.

lib/octocatalog-diff/catalog-diff/filter/single_item_array.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require_relative '../filter'
+
+require 'set'
+
+module OctocatalogDiff
+  module CatalogDiff
+    class Filter
+      # Filter out changes in parameters when one catalog has a parameter that's a string and
+      # the other catalog has that same parameter as an array containing the same string.
+      # For example, under this filter, the following is not a change:
+      #   catalog1: notify => "Service[foo]"
+      #   catalog2: notify => ["Service[foo]"]
+      class SingleItemArray < OctocatalogDiff::CatalogDiff::Filter
+        # Public: Implement the filter for single-item arrays whose item exactly matches the
+        # item that's not in an array in the other catalog.
+        #
+        # @param diff [OctocatalogDiff::API::V1::Diff] Difference
+        # @param _options [Hash] Additional options (there are none for this filter)
+        # @return [Boolean] true if this difference is a YAML file with identical objects, false otherwise
+        def filtered?(_diff, _options = {})
+          false
+        end
+      end
+    end
+  end
+end