Add spec for pages

spec/lib/bitbucket_server/page_spec.rb

+require 'spec_helper'
+
+describe BitbucketServer::Page do
+  let(:response) { { 'values' => [{ 'description' => 'Test' }], 'isLastPage' => false, 'nextPageStart' => 2 } }
+
+  before do
+    # Autoloading hack
+    BitbucketServer::Representation::PullRequest.new({})
+  end
+
+  describe '#items' do
+    it 'returns collection of needed objects' do
+      page = described_class.new(response, :pull_request)
+
+      expect(page.items.first).to be_a(BitbucketServer::Representation::PullRequest)
+      expect(page.items.count).to eq(1)
+    end
+  end
+
+  describe '#attrs' do
+    it 'returns attributes' do
+      page = described_class.new(response, :pull_request)
+
+      expect(page.attrs.keys).to include(:isLastPage, :nextPageStart)
+    end
+  end
+
+  describe '#next?' do
+    it 'returns true' do
+      page = described_class.new(response, :pull_request)
+
+      expect(page.next?).to be_truthy
+    end
+
+    it 'returns false' do
+      response['isLastPage'] = true
+      response.delete('nextPageStart')
+      page = described_class.new(response, :pull_request)
+
+      expect(page.next?).to be_falsey
+    end
+  end
+
+  describe '#next' do
+    it 'returns next attribute' do
+      page = described_class.new(response, :pull_request)
+
+      expect(page.next).to eq(2)
+    end
+  end
+end