1 files changed, 97 insertions, 0 deletions
diff --git a/spec/lib/gitlab/graphql/pagination/connections_spec.rb b/spec/lib/gitlab/graphql/pagination/connections_spec.rb
new file mode 100644
index 00000000000..e89e5c17644
--- /dev/null
+++ b/spec/lib/gitlab/graphql/pagination/connections_spec.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+# Tests that our connections are correctly mapped.
+RSpec.describe ::Gitlab::Graphql::Pagination::Connections do
+  include GraphqlHelpers
+
+  before(:all) do
+    ActiveRecord::Schema.define do
+      create_table :testing_pagination_nodes, force: true do |t|
+        t.integer :value, null: false
+      end
+    end
+  end
+
+  after(:all) do
+    ActiveRecord::Schema.define do
+      drop_table :testing_pagination_nodes, force: true
+    end
+  end
+
+  let_it_be(:node_model) do
+    Class.new(ActiveRecord::Base) do
+      self.table_name = 'testing_pagination_nodes'
+    end
+  end
+
+  let(:query_string) { 'query { items(first: 2) { nodes { value } } }' }
+  let(:user) { nil }
+
+  let(:node) { Struct.new(:value) }
+  let(:node_type) do
+    Class.new(::GraphQL::Schema::Object) do
+      graphql_name 'Node'
+      field :value, GraphQL::INT_TYPE, null: false
+    end
+  end
+
+  let(:query_type) do
+    item_values = nodes
+
+    query_factory do |t|
+      t.field :items, node_type.connection_type, null: true
+
+      t.define_method :items do
+        item_values
+      end
+    end
+  end
+
+  shared_examples 'it maps to a specific connection class' do |connection_type|
+    let(:raw_values) { [1, 7, 42] }
+
+    it "maps to #{connection_type.name}" do
+      expect(connection_type).to receive(:new).and_call_original
+
+      results = execute_query(query_type).to_h
+
+      expect(graphql_dig_at(results, :data, :items, :nodes, :value)).to eq [1, 7]
+    end
+  end
+
+  describe 'OffsetPaginatedRelation' do
+    before do
+      # Expect to be ordered by an explicit ordering.
+      raw_values.each_with_index { |value, id| node_model.create!(id: id, value: value) }
+    end
+
+    let(:nodes) { ::Gitlab::Graphql::Pagination::OffsetPaginatedRelation.new(node_model.order(value: :asc)) }
+
+    include_examples 'it maps to a specific connection class', Gitlab::Graphql::Pagination::OffsetActiveRecordRelationConnection
+  end
+
+  describe 'ActiveRecord::Relation' do
+    before do
+      # Expect to be ordered by ID descending
+      [3, 2, 1].zip(raw_values) { |id, value| node_model.create!(id: id, value: value) }
+    end
+
+    let(:nodes) { node_model.all }
+
+    include_examples 'it maps to a specific connection class', Gitlab::Graphql::Pagination::Keyset::Connection
+  end
+
+  describe 'ExternallyPaginatedArray' do
+    let(:nodes) { ::Gitlab::Graphql::ExternallyPaginatedArray.new(nil, nil, node.new(1), node.new(7)) }
+
+    include_examples 'it maps to a specific connection class', Gitlab::Graphql::Pagination::ExternallyPaginatedArrayConnection
+  end
+
+  describe 'Array' do
+    let(:nodes) { raw_values.map { |x| node.new(x) } }
+
+    include_examples 'it maps to a specific connection class', Gitlab::Graphql::Pagination::ArrayConnection
+  end
+end