Add api address external data fetch

spec/lib/api_address/address_adapter_spec.rb

@@ -0,0 +1,45 @@
+describe APIAddress::AddressAdapter do
+  let(:search_term) { 'Paris' }
+  let(:adapter) { described_class.new(search_term) }
+  subject { adapter.to_params }
+
+  before do
+    Geocoder.configure(lookup: :ban_data_gouv_fr, use_https: true)
+    stub_request(:get, /https:\/\/api-adresse.data.gouv.fr\/search/)
+      .to_return(body: body, status: status)
+  end
+
+  after do
+    Geocoder.configure(lookup: :test)
+  end
+
+  context "when responds with valid schema" do
+    let(:body) { File.read('spec/fixtures/files/api_address/address.json') }
+    let(:status) { 200 }
+
+    it '#to_params returns a valid' do
+      expect(subject).to be_an_instance_of(Hash)
+      expect(subject[:city_name]).to eq(search_term)
+      expect(subject[:city_code]).to eq('75056')
+    end
+  end
+
+  context "when responds with an address which is not a direct match to search term" do
+    let(:body) { File.read('spec/fixtures/files/api_address/address.json') }
+    let(:status) { 200 }
+    let(:search_term) { 'Lyon' }
+
+    it '#to_params ignores the response' do
+      expect(subject).to be_nil
+    end
+  end
+
+  context "when responds with invalid schema" do
+    let(:body) { File.read('spec/fixtures/files/api_address/address_invalid.json') }
+    let(:status) { 200 }
+
+    it '#to_params raise exception' do
+      expect { subject }.to raise_exception(APIAddress::AddressAdapter::InvalidSchemaError)
+    end
+  end
+end