diff --git a/app/models/gcp/cluster.rb b/app/models/gcp/cluster.rb
index 21eab9d8c1cfa9d690b30746939591daf0de078d..367e9be578ceca4da8090b0d1eb02c31d42a8c03 100644
--- a/app/models/gcp/cluster.rb
+++ b/app/models/gcp/cluster.rb
@@ -84,7 +84,7 @@ module Gcp
         cluster.gcp_operation_id = nil
       end
 
-      before_transition any => [:errored] do |cluster|
+      before_transition any => [:errored] do |cluster, transition|
         status_reason = transition.args.first
         cluster.status_reason = status_reason
       end
diff --git a/spec/factories/gcp/cluster.rb b/spec/factories/gcp/cluster.rb
new file mode 100644
index 0000000000000000000000000000000000000000..ea42c71664967a90f59b1074ede6f3d841b361ec
--- /dev/null
+++ b/spec/factories/gcp/cluster.rb
@@ -0,0 +1,23 @@
+FactoryGirl.define do
+  factory :gcp_cluster, class: Gcp::Cluster do
+    project
+    user
+    enabled true
+    gcp_project_id 'gcp-project-12345'
+    gcp_cluster_name 'test-cluster'
+    gcp_cluster_zone 'us-central1-a'
+    gcp_cluster_size 1
+
+    trait :with_kubernetes_service do
+      service :kubernetes_service
+    end
+
+    trait :created_on_gke do
+      endpoint '111.111.111.111'
+      ca_cert 'xxxxxx'
+      kubernetes_token 'xxxxxx'
+      username 'xxxxxx'
+      password 'xxxxxx'
+    end
+  end
+end
diff --git a/spec/models/gcp/cluster_spec.rb b/spec/models/gcp/cluster_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..5e4c35e24ffe7947256614abe9b0f93555963f4e
--- /dev/null
+++ b/spec/models/gcp/cluster_spec.rb
@@ -0,0 +1,266 @@
+require 'spec_helper'
+
+describe Gcp::Cluster do
+  it { is_expected.to belong_to(:project) }
+  it { is_expected.to belong_to(:user) }
+  it { is_expected.to belong_to(:service) }
+
+  it { is_expected.to validate_presence_of(:gcp_cluster_zone) }
+
+  describe '#default_value_for' do
+    let(:cluster) { described_class.new }
+
+    it { expect(cluster.gcp_cluster_zone).to eq('us-central1-a') }
+    it { expect(cluster.gcp_cluster_size).to eq(3) }
+    it { expect(cluster.gcp_machine_type).to eq('n1-standard-4') }
+  end
+
+  describe '#validates' do
+    subject { cluster.valid? }
+
+    context 'when validates gcp_project_id' do
+      let(:cluster) { build(:gcp_cluster, gcp_project_id: gcp_project_id) }
+
+      context 'when valid' do
+        let(:gcp_project_id) { 'gcp-project-12345' }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when empty' do
+        let(:gcp_project_id) { '' }
+
+        it { is_expected.to be_falsey }
+      end
+
+      context 'when too long' do
+        let(:gcp_project_id) { 'A'*64 }
+
+        it { is_expected.to be_falsey }
+      end
+
+      context 'when includes abnormal character' do
+        let(:gcp_project_id) { '!!!!!!' }
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
+    context 'when validates gcp_cluster_name' do
+      let(:cluster) { build(:gcp_cluster, gcp_cluster_name: gcp_cluster_name) }
+
+      context 'when valid' do
+        let(:gcp_cluster_name) { 'test-cluster' }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when empty' do
+        let(:gcp_cluster_name) { '' }
+
+        it { is_expected.to be_falsey }
+      end
+
+      context 'when too long' do
+        let(:gcp_cluster_name) { 'A'*64 }
+
+        it { is_expected.to be_falsey }
+      end
+
+      context 'when includes abnormal character' do
+        let(:gcp_cluster_name) { '!!!!!!' }
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
+    context 'when validates gcp_cluster_size' do
+      let(:cluster) { build(:gcp_cluster, gcp_cluster_size: gcp_cluster_size) }
+
+      context 'when valid' do
+        let(:gcp_cluster_size) { 1 }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when zero' do
+        let(:gcp_cluster_size) { 0 }
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
+    context 'when validates project_namespace' do
+      let(:cluster) { build(:gcp_cluster, project_namespace: project_namespace) }
+
+      context 'when valid' do
+        let(:project_namespace) { 'default-namespace' }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when empty' do
+        let(:project_namespace) { '' }
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when too long' do
+        let(:project_namespace) { 'A'*64 }
+
+        it { is_expected.to be_falsey }
+      end
+
+      context 'when includes abnormal character' do
+        let(:project_namespace) { '!!!!!!' }
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
+    context 'when validates restrict_modification' do
+      let(:cluster) { create(:gcp_cluster) }
+
+      before do
+        cluster.creating!
+      end
+
+      context 'when created' do
+        before do
+          cluster.created!
+        end
+
+        it { is_expected.to be_truthy }
+      end
+
+      context 'when creating' do
+        it { is_expected.to be_falsey }
+      end
+    end
+  end
+
+  describe '#state_machine' do
+    let(:cluster) { build(:gcp_cluster) }
+
+    context 'when transits to created state' do
+      before do
+        cluster.gcp_token = 'tmp'
+        cluster.gcp_operation_id = 'tmp'
+        cluster.make_created!
+      end
+
+      it 'nullify gcp_token and gcp_operation_id' do
+        expect(cluster.gcp_token).to be_nil
+        expect(cluster.gcp_operation_id).to be_nil
+        expect(cluster).to be_created
+      end
+    end
+
+    context 'when transits to errored state' do
+      let(:reason) { 'something wrong' }
+
+      before do
+        cluster.make_errored!(reason)
+      end
+
+      it 'sets status_reason' do
+        expect(cluster.status_reason).to eq(reason)
+        expect(cluster).to be_errored
+      end
+    end
+  end
+
+  describe '#project_namespace_placeholder' do
+    subject { cluster.project_namespace_placeholder }
+
+    let(:cluster) { create(:gcp_cluster) }
+
+    it 'returns a placeholder' do
+      is_expected.to eq("#{cluster.project.path}-#{cluster.project.id}")
+    end
+  end
+
+  describe '#on_creation?' do
+    subject { cluster.on_creation? }
+
+    let(:cluster) { create(:gcp_cluster) }
+
+    context 'when status is creating' do
+      before do
+        cluster.make_creating!
+      end
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when status is created' do
+      before do
+        cluster.make_created!
+      end
+
+      it { is_expected.to be_falsey }
+    end
+  end
+
+  describe '#api_url' do
+    subject { cluster.api_url }
+
+    let(:cluster) { create(:gcp_cluster, :created_on_gke) }
+    let(:api_url) { 'https://' + cluster.endpoint }
+
+    it { is_expected.to eq(api_url) }
+  end
+
+  describe '#restrict_modification' do
+    subject { cluster.restrict_modification }
+
+    let(:cluster) { create(:gcp_cluster) }
+
+    context 'when status is created' do
+      before do
+        cluster.make_created!
+      end
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when status is creating' do
+      before do
+        cluster.make_creating!
+      end
+
+      it { is_expected.to be_falsey }
+
+      it 'sets error' do
+        is_expected.to be_falsey
+        expect(cluster.errors).not_to be_empty
+      end
+    end
+  end
+
+  describe '#destroy' do
+    subject { cluster.destroy }
+
+    let(:cluster) { create(:gcp_cluster) }
+
+    context 'when status is created' do
+      before do
+        cluster.make_created!
+      end
+
+      it 'destory the cluster' do
+        is_expected.to eq(cluster)
+      end
+    end
+
+    context 'when status is creating' do
+      before do
+        cluster.make_creating!
+      end
+
+      it 'does not destory the cluster' do
+        is_expected.to be_nil
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/create_cluster_service_spec.rb b/spec/services/ci/create_cluster_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..eaa27eb4cc36fc08cbf6f2b03ae4a1d9c2ae4b59
--- /dev/null
+++ b/spec/services/ci/create_cluster_service_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+describe Ci::CreateClusterService do
+  describe '#execute' do
+    let(:access_token) { 'xxx' }
+
+    context 'when correct params' do
+      it 'creates a cluster object' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'returns an error' do
+
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/fetch_gcp_operation_service_spec.rb b/spec/services/ci/fetch_gcp_operation_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..13141d81ab8f37ff56a5511357d504e579fced13
--- /dev/null
+++ b/spec/services/ci/fetch_gcp_operation_service_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::FetchGcpOperationService do
+  describe '#execute' do
+    context 'when correct params' do
+      it 'fetch the gcp operaion' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'sets an error to cluster object' do
+
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/fetch_kubernetes_token_service_spec.rb b/spec/services/ci/fetch_kubernetes_token_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..b66b5a7947db7db8cb53fb412d84cea6023efdea
--- /dev/null
+++ b/spec/services/ci/fetch_kubernetes_token_service_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::FetchKubernetesTokenService do
+  describe '#execute' do
+    context 'when correct params' do
+      it 'fetch the kubernetes token' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'returns nil' do
+
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/finalize_cluster_creation_service_spec.rb b/spec/services/ci/finalize_cluster_creation_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..81af15942c09de2bb7b2ab141965a9e96bc5f9bf
--- /dev/null
+++ b/spec/services/ci/finalize_cluster_creation_service_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::FinalizeClusterCreationService do
+  describe '#execute' do
+    context 'when correct params' do
+      it 'execute IntegrateClusterService' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'returns a cluster object with error' do
+
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/integrate_cluster_service_spec.rb b/spec/services/ci/integrate_cluster_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..7a8c80ca4e737c5c8ad72e1e43064cfa26a891f2
--- /dev/null
+++ b/spec/services/ci/integrate_cluster_service_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::IntegrateClusterService do
+  describe '#execute' do
+    context 'when correct params' do
+      it 'creates a cluster object' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'returns a cluster object with error' do
+
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/provision_cluster_service_spec.rb b/spec/services/ci/provision_cluster_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..d1595c8917d9ae2bc3064b8c46fe774a04af0a76
--- /dev/null
+++ b/spec/services/ci/provision_cluster_service_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::ProvisionClusterService do
+  describe '#execute' do
+    context 'when correct params' do
+      it 'creates a cluster on gke' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'returns a cluster object with error' do
+
+      end
+    end
+  end
+end
diff --git a/spec/services/ci/update_cluster_service_spec.rb b/spec/services/ci/update_cluster_service_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..afe3d418a8e455bdaa270f9b0250381373689ff8
--- /dev/null
+++ b/spec/services/ci/update_cluster_service_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Ci::UpdateClusterService do
+  describe '#execute' do
+    context 'when correct params' do
+      it 'updates the cluster and the service' do
+        
+      end
+    end
+
+    context 'when invalid params' do
+      it 'returns a cluster object with error' do
+
+      end
+    end
+  end
+end