add service Geojson to_polygon

app/services/geojson_service.rb

@@ -0,0 +1,10 @@
+class GeojsonService
+  def self.to_polygon coordinates
+    {
+        geo: {
+            type: "Polygon",
+            coordinates: [coordinates]
+        }
+    }
+  end
+end

spec/services/geojson_service_spec.rb

@@ -0,0 +1,42 @@
+require 'spec_helper'
+
+describe GeojsonService do
+  describe '.toGeoJsonPolygon' do
+
+    let(:to_polygon_return) {
+      {
+          geo: {
+              type: "Polygon",
+              coordinates: [coordinates]
+          }
+      }
+    }
+
+    subject { described_class.to_polygon coordinates }
+
+    describe 'coordinates are empty' do
+      let(:coordinates) { '' }
+
+      it { expect(subject).to eq(to_polygon_return) }
+    end
+
+    describe 'coordinates are informed' do
+      let(:coordinates) {
+        [
+            [5.93536376953125,
+             48.91888968903368],
+            [5.93536376953125,
+             49.26780455063753],
+            [7.094421386718749,
+             49.26780455063753],
+            [7.094421386718749,
+             48.91888968903368],
+            [5.93536376953125,
+             48.91888968903368]
+        ]
+      }
+
+      it { expect(subject).to eq(to_polygon_return) }
+    end
+  end
+end