Add round trip tests for conversion to go-openapi types

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/validation/BUILD

@@ -3,6 +3,7 @@ package(default_visibility = ["//visibility:public"])
 load(
     "@io_bazel_rules_go//go:def.bzl",
     "go_library",
+    "go_test",
 )
 
 go_library(
@@ -27,3 +28,20 @@ filegroup(
     srcs = [":package-srcs"],
     tags = ["automanaged"],
 )
+
+go_test(
+    name = "go_default_test",
+    srcs = ["validation_test.go"],
+    library = ":go_default_library",
+    deps = [
+        "//vendor/github.com/go-openapi/spec:go_default_library",
+        "//vendor/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions:go_default_library",
+        "//vendor/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/fuzzer:go_default_library",
+        "//vendor/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/equality:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/testing/fuzzer:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/runtime/serializer:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/json:go_default_library",
+    ],
+)

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/validation/validation_test.go

@@ -0,0 +1,87 @@
+/*
+Copyright 2017 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 validation
+
+import (
+	"math/rand"
+	"testing"
+
+	"github.com/go-openapi/spec"
+
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
+	"k8s.io/apimachinery/pkg/api/testing/fuzzer"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	"k8s.io/apimachinery/pkg/util/json"
+
+	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
+	apiextensionsfuzzer "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/fuzzer"
+	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
+)
+
+// TestRoundTrip checks the conversion to go-openapi types.
+// internal -> go-openapi -> JSON -> external -> internal
+func TestRoundTrip(t *testing.T) {
+	scheme := runtime.NewScheme()
+	codecs := serializer.NewCodecFactory(scheme)
+
+	// add internal and external types to scheme
+	if err := apiextensions.AddToScheme(scheme); err != nil {
+		t.Fatal(err)
+	}
+	if err := apiextensionsv1beta1.AddToScheme(scheme); err != nil {
+		t.Fatal(err)
+	}
+
+	seed := rand.Int63()
+	fuzzerFuncs := fuzzer.MergeFuzzerFuncs(apiextensionsfuzzer.Funcs)
+	f := fuzzer.FuzzerFor(fuzzerFuncs, rand.NewSource(seed), codecs)
+
+	for i := 0; i < 20; i++ {
+		// fuzz internal types
+		internal := &apiextensions.JSONSchemaProps{}
+		f.Fuzz(internal)
+
+		// internal -> go-openapi
+		openAPITypes := &spec.Schema{}
+		if err := convertJSONSchemaProps(internal, openAPITypes); err != nil {
+			t.Fatal(err)
+		}
+
+		// go-openapi -> JSON
+		openAPIJSON, err := json.Marshal(openAPITypes)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// JSON -> external
+		external := &apiextensionsv1beta1.JSONSchemaProps{}
+		if err := json.Unmarshal(openAPIJSON, external); err != nil {
+			t.Fatal(err)
+		}
+
+		// external -> internal
+		internalRoundTripped := &apiextensions.JSONSchemaProps{}
+		if err := scheme.Convert(external, internalRoundTripped, nil); err != nil {
+			t.Fatal(err)
+		}
+
+		if !apiequality.Semantic.DeepEqual(internal, internalRoundTripped) {
+			t.Fatalf("expected\n\t%#v, got \n\t%#v", internal, internalRoundTripped)
+		}
+	}
+}