Add tests for initialization on InstalledAppFlow (#275)

spec/google/api_client/auth/installed_app_spec.rb

@@ -0,0 +1,41 @@
+require 'spec_helper'
+
+require 'google/api_client/auth/installed_app'
+
+describe Google::APIClient::InstalledAppFlow do
+  let(:secrets) do 
+    file = File.join(FIXTURES_DIR, 'files', 'client_secrets.json')
+    Google::APIClient::ClientSecrets.load(file)
+  end
+
+  subject(:flow) { Google::APIClient::InstalledAppFlow.new(
+    :client_id => secrets.client_id,
+    :client_secret => secrets.client_secret, 
+    :scope => 'https://www.googleapis.com/auth/drive.metadata.readonly',
+    :port => 5000)}
+
+  context 'initialization' do
+
+    it 'should be valid instance' do
+      expect(flow).to be_a Google::APIClient::InstalledAppFlow
+    end
+
+    it 'should have valid port' do
+      expect(flow.instance_variable_get("@port")).to eq 5000
+    end
+
+    it 'should have default port' do
+      another_flow = Google::APIClient::InstalledAppFlow.new(
+        :client_id => secrets.client_id,
+        :client_secret => secrets.client_secret,
+        :scope => 'https://www.googleapis.com/auth/drive.metadata.readonly') 
+      expect(another_flow.instance_variable_get("@port")).to eq 9292
+    end
+    
+    it 'should have valid client_id' do
+      auth = flow.instance_variable_get "@authorization"
+      expect(auth.client_id).to eq "898243283568.apps.googleusercontent.com"
+    end
+    
+  end
+end