diff --git a/test/integration/apiserver/openapi_test.go b/test/integration/apiserver/openapi_test.go
new file mode 100644
index 00000000000..6d320f42779
--- /dev/null
+++ b/test/integration/apiserver/openapi_test.go
@@ -0,0 +1,115 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+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.
+*/
+
+package apiserver
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"k8s.io/apiserver/pkg/features"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/apiserver/pkg/util/openapi"
+	restclient "k8s.io/client-go/rest"
+	featuregatetesting "k8s.io/component-base/featuregate/testing"
+	"k8s.io/kube-openapi/pkg/common"
+	"k8s.io/kube-openapi/pkg/validation/spec"
+	generated "k8s.io/kubernetes/pkg/generated/openapi"
+	"k8s.io/kubernetes/test/integration/framework"
+)
+
+func TestEnablingOpenAPIEnumTypes(t *testing.T) {
+	const typeToAddEnum = "k8s.io/api/core/v1.ContainerPort"
+	const typeToCheckEnum = "io.k8s.api.core.v1.ContainerPort"
+
+	for _, tc := range []struct {
+		name            string
+		featureEnabled  bool
+		enumShouldExist bool
+	}{
+		{
+			name:            "disabled",
+			featureEnabled:  false,
+			enumShouldExist: false,
+		},
+		{
+			name:            "enabled",
+			featureEnabled:  true,
+			enumShouldExist: true,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.OpenAPIEnums, tc.featureEnabled)()
+
+			controlPlaneConfig := framework.NewIntegrationTestControlPlaneConfigWithOptions(&framework.ControlPlaneConfigOptions{})
+			controlPlaneConfig.GenericConfig.OpenAPIConfig = framework.DefaultOpenAPIConfig()
+			controlPlaneConfig.GenericConfig.OpenAPIConfig.GetDefinitions = openapi.GetOpenAPIDefinitionsWithoutDisabledFeatures(func(ref common.ReferenceCallback) map[string]common.OpenAPIDefinition {
+				defs := generated.GetOpenAPIDefinitions(ref)
+				def := defs[typeToAddEnum]
+				// replace protocol to add the would-be enum field.
+				def.Schema.Properties["protocol"] = spec.Schema{
+					SchemaProps: spec.SchemaProps{
+						Description: "Protocol for port. Must be UDP, TCP, or SCTP. Defaults to \\\"TCP\\\".\\n\\nPossible enum values:\\n - `SCTP`: is the SCTP protocol.\\n - `TCP`: is the TCP protocol.\\n - `UDP`: is the UDP protocol.",
+						Default:     "TCP",
+						Type:        []string{"string"},
+						Format:      "",
+						Enum:        []interface{}{"SCTP", "TCP", "UDP"},
+					},
+				}
+				defs[typeToAddEnum] = def
+				return defs
+			})
+
+			instanceConfig, _, closeFn := framework.RunAnAPIServer(controlPlaneConfig)
+			defer closeFn()
+
+			rt, err := restclient.TransportFor(instanceConfig.GenericAPIServer.LoopbackClientConfig)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			req, err := http.NewRequest("GET", instanceConfig.GenericAPIServer.LoopbackClientConfig.Host+"/openapi/v2", nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+			resp, err := rt.RoundTrip(req)
+			if err != nil {
+				t.Fatal(err)
+			}
+			var body struct {
+				Definitions map[string]struct {
+					Properties map[string]struct {
+						Description string   `json:"description"`
+						Type        string   `json:"type"`
+						Enum        []string `json:"enum"`
+					} `json:"properties"`
+				} `json:"definitions"`
+			}
+			err = json.NewDecoder(resp.Body).Decode(&body)
+			if err != nil {
+				t.Fatal(err)
+			}
+			protocol, ok := body.Definitions[typeToCheckEnum].Properties["protocol"]
+			if !ok {
+				t.Fatalf("protocol not found in properties in %v", body)
+			}
+			if enumExists := len(protocol.Enum) > 0; enumExists != tc.enumShouldExist {
+				t.Errorf("expect enum exists: %v, but got %v", tc.enumShouldExist, enumExists)
+			}
+		})
+	}
+}