diff --git a/pkg/master/master_test.go b/pkg/master/master_test.go
index 132f45caac..0772ef88ed 100644
--- a/pkg/master/master_test.go
+++ b/pkg/master/master_test.go
@@ -918,3 +918,54 @@ func testInstallThirdPartyResourceRemove(t *testing.T, version string) {
 		}
 	}
 }
+
+func TestThirdPartyDiscovery(t *testing.T) {
+	for _, version := range versionsToTest {
+		testThirdPartyDiscovery(t, version)
+	}
+}
+
+func testThirdPartyDiscovery(t *testing.T, version string) {
+	_, etcdserver, server, assert := initThirdParty(t, version)
+	// TODO: Uncomment when fix #19254
+	// defer server.Close()
+	defer etcdserver.Terminate(t)
+
+	resp, err := http.Get(server.URL + "/apis/company.com/")
+	if !assert.NoError(err) {
+		return
+	}
+	assert.Equal(http.StatusOK, resp.StatusCode)
+
+	group := unversioned.APIGroup{}
+	assert.NoError(decodeResponse(resp, &group))
+	assert.Equal(group.APIVersion, "v1")
+	assert.Equal(group.Kind, "APIGroup")
+	assert.Equal(group.Name, "company.com")
+	assert.Equal(group.Versions, []unversioned.GroupVersionForDiscovery{
+		{
+			GroupVersion: "company.com/" + version,
+			Version:      version,
+		},
+	})
+	assert.Equal(group.PreferredVersion, unversioned.GroupVersionForDiscovery{})
+
+	resp, err = http.Get(server.URL + "/apis/company.com/" + version)
+	if !assert.NoError(err) {
+		return
+	}
+	assert.Equal(http.StatusOK, resp.StatusCode)
+
+	resourceList := unversioned.APIResourceList{}
+	assert.NoError(decodeResponse(resp, &resourceList))
+	assert.Equal(resourceList.APIVersion, "v1")
+	assert.Equal(resourceList.Kind, "APIResourceList")
+	assert.Equal(resourceList.GroupVersion, "company.com/"+version)
+	assert.Equal(resourceList.APIResources, []unversioned.APIResource{
+		{
+			Name:       "foos",
+			Namespaced: true,
+			Kind:       "Foo",
+		},
+	})
+}
diff --git a/pkg/registry/thirdpartyresourcedata/codec.go b/pkg/registry/thirdpartyresourcedata/codec.go
index 5ca3943d38..bbc99ee8f9 100644
--- a/pkg/registry/thirdpartyresourcedata/codec.go
+++ b/pkg/registry/thirdpartyresourcedata/codec.go
@@ -324,7 +324,7 @@ func (t *thirdPartyResourceDataCodec) EncodeToStream(obj runtime.Object, stream
 		}
 		fmt.Fprintf(stream, template, t.kind+"List", strings.Join(dataStrings, ","))
 		return nil
-	case *unversioned.Status:
+	case *unversioned.Status, *unversioned.APIResourceList:
 		return t.delegate.EncodeToStream(obj, stream, overrides...)
 	default:
 		return fmt.Errorf("unexpected object to encode: %#v", obj)