Add modulo operator (#21)

* Add modulo operator

* Remove unnecessary matching function

* Uncomment test cases

Author: matthewelwell

lib/flagsmith/engine/segments/constants.rb

@@ -22,6 +22,7 @@ module Constants
         NOT_EQUAL = 'NOT_EQUAL'
         REGEX = 'REGEX'
         PERCENTAGE_SPLIT = 'PERCENTAGE_SPLIT'
+        MODULO = 'MODULO'
 
         CONDITION_OPERATORS = [
           EQUAL,
@@ -33,7 +34,8 @@ module Constants
           NOT_CONTAINS,
           NOT_EQUAL,
           REGEX,
-          PERCENTAGE_SPLIT
+          PERCENTAGE_SPLIT,
+          MODULO
         ].freeze
       end
     end

lib/flagsmith/engine/segments/models.rb

@@ -55,10 +55,13 @@ def initialize(operator:, value:, property: nil)
         end
 
         def match_trait_value?(trait_value)
+          # handle some exceptions
           if @value.is_a?(String) && @value.match?(/:semver$/)
             trait_value = Semantic::Version.new(trait_value.gsub(/:semver$/, ''))
           end
 
+          return match_modulo_value(trait_value) if @operator == MODULO
+
           type_as_trait_value = format_to_type_of(trait_value)
           formatted_value = type_as_trait_value ? type_as_trait_value.call(@value) : @value
 
@@ -78,6 +81,13 @@ def format_to_type_of(input)
         end
         # rubocop:enable Metrics/AbcSize
 
+        def match_modulo_value(trait_value)
+          divisor, remainder = @value.split('|')
+          trait_value.is_a?(Numeric) && trait_value % divisor.to_f == remainder.to_f
+        rescue StandardError
+          false
+        end
+
         class << self
           def build(json)
             new(**json.slice(:operator, :value).merge(property: json[:property_]))

spec/engine/unit/segments/models_spec.rb

@@ -73,7 +73,12 @@
   ['GREATER_THAN_INCLUSIVE', '1.0.1', '1.0.1:semver', true],
   ['LESS_THAN_INCLUSIVE', '1.0.0', '1.0.1:semver', true],
   ['LESS_THAN_INCLUSIVE', '1.0.0', '1.0.0:semver', true],
-  ['LESS_THAN_INCLUSIVE', '1.0.1', '1.0.0:semver', false]
+  ['LESS_THAN_INCLUSIVE', '1.0.1', '1.0.0:semver', false],
+  ['MODULO', 2, '2|0', true],
+  ['MODULO', 3, '2|0', false],
+  ['MODULO', 2.0, '2|0', true],
+  ['MODULO', 'foo', '2|0', false],
+  ['MODULO', 'foo', 'foo|bar', false],
 ].freeze
 
 RSpec.describe Flagsmith::Engine::Segments::Condition do