diff --git a/tests/immutable_test.go b/tests/immutable_test.go
new file mode 100644
index 000000000..2869536e4
--- /dev/null
+++ b/tests/immutable_test.go
@@ -0,0 +1,135 @@
+//
+// DISCLAIMER
+//
+// Copyright 2018 ArangoDB GmbH, Cologne, Germany
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+// Author Kaveh Vahedipour
+// Author Ewout Prangsma
+//
+
+package tests
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/dchest/uniuri"
+
+	api "github.com/arangodb/kube-arangodb/pkg/apis/deployment/v1alpha"
+	"github.com/arangodb/kube-arangodb/pkg/client"
+)
+
+// TestImmutableFields tests that several immutable fields in the deployment
+// spec are reverted to their original value.
+func TestImmutableFields(t *testing.T) {
+	longOrSkip(t)
+	c := client.MustNewInCluster()
+	kubecli := mustNewKubeClient(t)
+	ns := getNamespace(t)
+	revertTimeout := time.Second * 30
+
+	// Prepare deployment config
+	depl := newDeployment("test-ise-" + uniuri.NewLen(4))
+	depl.Spec.Mode = api.NewMode(api.DeploymentModeSingle)
+	depl.Spec.SetDefaults(depl.GetName())
+
+	// Create deployment
+	apiObject, err := c.DatabaseV1alpha().ArangoDeployments(ns).Create(depl)
+	if err != nil {
+		t.Fatalf("Create deployment failed: %v", err)
+	}
+
+	// Wait for deployment to be ready
+	if _, err := waitUntilDeployment(c, depl.GetName(), ns, deploymentHasState(api.DeploymentStateRunning)); err != nil {
+		t.Fatalf("Deployment not running in time: %v", err)
+	}
+
+	// Create a database client
+	ctx := context.Background()
+	client := mustNewArangodDatabaseClient(ctx, kubecli, apiObject, t)
+
+	// Wait for single server to be completely ready
+	if err := waitUntilVersionUp(client); err != nil {
+		t.Fatalf("Single server not up in time: %v", err)
+	}
+
+	// Try to reset storageEngine ===============================================
+	if _, err := updateDeployment(c, depl.GetName(), ns,
+		func(spec *api.DeploymentSpec) {
+			spec.StorageEngine = api.NewStorageEngine(api.StorageEngineMMFiles)
+		}); err != nil {
+		t.Fatalf("Failed to update the StorageEngine setting: %v", err)
+	}
+
+	// Wait for StorageEngine parameter to be back to RocksDB
+	if _, err := waitUntilDeployment(c, depl.GetName(), ns,
+		func(depl *api.ArangoDeployment) error {
+			if api.StorageEngineOrDefault(depl.Spec.StorageEngine) == api.StorageEngineRocksDB {
+				return nil
+			}
+			return fmt.Errorf("StorageEngine not back to %s", api.StorageEngineRocksDB)
+		}, revertTimeout); err != nil {
+		t.Errorf("StorageEngine parameter is immutable: %v", err)
+	}
+
+	/*
+		 Secrets are a special case that we'll deal with later
+		// Try to reset the RocksDB encryption key ==================================
+		if _, err := updateDeployment(c, depl.GetName(), ns,
+			func(spec *api.DeploymentSpec) {
+				spec.RocksDB.Encryption.KeySecretName = util.NewString("foobarbaz")
+			}); err != nil {
+			t.Fatalf("Failed to update the RocksDB encryption key: %v", err)
+		}
+
+		// Wait for deployment mode to be set back to cluster
+		if _, err := waitUntilDeployment(c, depl.GetName(), ns,
+			func(depl *api.ArangoDeployment) error {
+				if util.StringOrDefault(depl.Spec.RocksDB.Encryption.KeySecretName) == "test.encryption.keySecretName" {
+					return nil
+				}
+				return fmt.Errorf("RocksDB encryption key not back to %s", "test.encryption.keySecretName")
+			}, revertTimeout); err != nil {
+			t.Errorf("RocksDB encryption key is mutable: %v", err)
+		}
+	*/
+
+	// Try to reset the deployment type ==========================================
+	if _, err := updateDeployment(c, depl.GetName(), ns,
+		func(spec *api.DeploymentSpec) {
+			spec.Mode = api.NewMode(api.DeploymentModeCluster)
+		}); err != nil {
+		t.Fatalf("Failed to update the deployment mode: %v", err)
+	}
+
+	// Wait for deployment mode to be set back to cluster
+	if _, err := waitUntilDeployment(c, depl.GetName(), ns,
+		func(depl *api.ArangoDeployment) error {
+			expected := api.DeploymentModeSingle
+			if api.ModeOrDefault(depl.Spec.Mode) == expected {
+				return nil
+			}
+			return fmt.Errorf("Deployment mode not back to %s", expected)
+		}, revertTimeout); err != nil {
+		t.Errorf("Deployment mode is mutable: %v", err)
+	}
+
+	// Cleanup
+	removeDeployment(c, depl.GetName(), ns)
+}
diff --git a/tests/test_util.go b/tests/test_util.go
index fa187a3c5..c2ca4d164 100644
--- a/tests/test_util.go
+++ b/tests/test_util.go
@@ -116,7 +116,7 @@ func newDeployment(name string) *api.ArangoDeployment {
 
 // waitUntilDeployment waits until a deployment with given name in given namespace
 // reached a state where the given predicate returns true.
-func waitUntilDeployment(cli versioned.Interface, deploymentName, ns string, predicate func(*api.ArangoDeployment) error) (*api.ArangoDeployment, error) {
+func waitUntilDeployment(cli versioned.Interface, deploymentName, ns string, predicate func(*api.ArangoDeployment) error, timeout ...time.Duration) (*api.ArangoDeployment, error) {
 	var result *api.ArangoDeployment
 	op := func() error {
 		obj, err := cli.DatabaseV1alpha().ArangoDeployments(ns).Get(deploymentName, metav1.GetOptions{})
@@ -132,7 +132,11 @@ func waitUntilDeployment(cli versioned.Interface, deploymentName, ns string, pre
 		}
 		return nil
 	}
-	if err := retry.Retry(op, deploymentReadyTimeout); err != nil {
+	actualTimeout := deploymentReadyTimeout
+	if len(timeout) > 0 {
+		actualTimeout = timeout[0]
+	}
+	if err := retry.Retry(op, actualTimeout); err != nil {
 		return nil, maskAny(err)
 	}
 	return result, nil