Initial commit

services/data-repository/spec/unit/structures/collection_spec.rb

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+require 'minitest/autorun'
+require_relative '../../../structures/collection'
+
+include DataRepository
+
+describe Collection do
+  before do
+    @repository = DataRepository::Repository.new
+    @dummy_class = Class.new do
+      attr_accessor :id
+      def initialize(arguments={}); self.id = arguments.fetch(:id); end
+      def fetch; self; end
+      def to_hash; { id: id }; end
+      def ==(other); id.to_s == other.id.to_s; end
+    end
+
+    @defaults = { repository: @repository, member_class: @dummy_class}
+  end
+
+  describe '#add' do
+    it 'adds a member to the collection' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new(@defaults)
+      collection.add(member)
+      collection.to_a.must_include member
+    end
+  end
+
+  describe '#delete' do
+    it 'deletes a member from the collection' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new(@defaults)
+      collection.add(member)
+      collection.delete(member)
+      collection.to_a.wont_include member
+    end
+  end #delete
+
+  describe '#each' do
+    it 'yields members of the collection as the initialized member_class' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new(@defaults)
+      collection.add(member)
+      collection.store
+
+      rehydrated_collection = 
+        Collection.new(@defaults.merge(signature: collection.signature))
+      rehydrated_collection.fetch
+      rehydrated_collection.to_a.first.must_be_instance_of @dummy_class
+    end
+
+    it 'returns an enumerator if no block given' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new({ repository: @repository })
+      collection.add(member)
+      collection.store
+
+      rehydrated_collection = 
+        Collection.new(@defaults.merge(signature: collection.signature))
+      rehydrated_collection.fetch
+
+      enumerator = rehydrated_collection.each
+      enumerator.next.must_be_instance_of @dummy_class
+    end
+  end #each
+
+  describe '#fetch' do
+    it 'resets the collection with data from the data repository' do
+      member1     = @dummy_class.new(id: 1)
+      member2     = @dummy_class.new(id: 2)
+      collection  = Collection.new(@defaults)
+      collection.add(member1)
+      collection.store
+
+      rehydrated_collection = 
+        Collection.new(@defaults.merge(signature: collection.signature))
+      rehydrated_collection.add(member2) 
+
+      rehydrated_collection.to_a.must_include(member2)
+      rehydrated_collection.to_a.wont_include(member1)
+      rehydrated_collection.fetch
+      rehydrated_collection.to_a.must_include(member1)
+      rehydrated_collection.to_a.wont_include(member2)
+    end
+
+    it 'empties the collection if it was not persisted to the repository' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new(@defaults)
+      collection.add(member)
+      collection.to_a.length.must_equal 1
+      collection.fetch
+      collection.to_a.must_be_empty
+    end
+  end #fetch
+
+  describe '#store' do
+    it 'persists the collection to the data repository' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new(@defaults)
+      collection.add(member)
+      collection.store
+
+      rehydrated_collection = 
+        Collection.new(@defaults.merge(signature: collection.signature))
+      rehydrated_collection.fetch
+      rehydrated_collection.map { |member| member.id }.must_include member.id
+    end
+  end #store
+
+  describe '#to_json' do
+    it 'renders a JSON representation of the collection' do
+      member      = @dummy_class.new(id: 1)
+      collection  = Collection.new(@defaults)
+      collection.add(member)
+      collection.store
+
+      representation = JSON.parse(collection.to_json)
+      representation.size.must_equal 1
+      representation.first.fetch('id').must_equal member.id
+    end
+  end #to_json
+end # Collection
+