apiextensions: add fuzzer test that NewStructural is complete

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/schema/convert_test.go

@@ -0,0 +1,112 @@
+/*
+Copyright 2019 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 schema
+
+import (
+	"math/rand"
+	"reflect"
+	"testing"
+	"time"
+
+	fuzz "github.com/google/gofuzz"
+
+	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
+	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
+	"k8s.io/apimachinery/pkg/util/diff"
+	"k8s.io/apimachinery/pkg/util/json"
+)
+
+func TestStructuralRoundtripOrError(t *testing.T) {
+	f := fuzz.New()
+	seed := time.Now().UnixNano()
+	t.Logf("seed = %v", seed)
+	//seed = int64(1549012506261785182)
+	f.RandSource(rand.New(rand.NewSource(seed)))
+	f.Funcs(
+		func(s *apiextensions.JSON, c fuzz.Continue) {
+			*s = apiextensions.JSON(map[string]interface{}{"foo": float64(42.2)})
+		},
+		func(s *apiextensions.JSONSchemaPropsOrArray, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			if s.Schema != nil {
+				s.JSONSchemas = nil
+			} else if s.JSONSchemas == nil {
+				s.Schema = &apiextensions.JSONSchemaProps{}
+			}
+		},
+		func(s *apiextensions.JSONSchemaPropsOrBool, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			if s.Schema != nil {
+				s.Allows = false
+			}
+		},
+		func(s **string, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			if *s != nil && **s == "" {
+				*s = nil
+			}
+		},
+	)
+
+	f.MaxDepth(2)
+	f.NilChance(0.5)
+
+	for i := 0; i < 10000; i++ {
+		// fuzz a random field in JSONSchemaProps
+		origSchema := &apiextensions.JSONSchemaProps{}
+		x := reflect.ValueOf(origSchema).Elem()
+		n := rand.Intn(x.NumField())
+		if name := x.Type().Field(n).Name; name == "Example" || name == "ExternalDocs" {
+			// we drop these intentionally
+			continue
+		}
+		f.Fuzz(x.Field(n).Addr().Interface())
+		if origSchema.Nullable {
+			// non-empty type for nullable. nullable:true with empty type does not roundtrip because
+			// go-openapi does not allow to encode that (we use type slices otherwise).
+			origSchema.Type = "string"
+		}
+
+		// it roundtrips or NewStructural errors out. We should never drop anything
+		orig, err := NewStructural(origSchema)
+		if err != nil {
+			continue
+		}
+
+		// roundtrip through go-openapi, JSON, v1beta1 JSONSchemaProp, internal JSONSchemaProp
+		goOpenAPI := orig.ToGoOpenAPI()
+		bs, err := json.Marshal(goOpenAPI)
+		if err != nil {
+			t.Fatal(err)
+		}
+		str := nullTypeRE.ReplaceAllString(string(bs), `"type":"$1","nullable":true`) // unfold nullable type:[<type>,"null"] -> type:<type>,nullable:true
+		v1beta1Schema := &apiextensionsv1beta1.JSONSchemaProps{}
+		err = json.Unmarshal([]byte(str), v1beta1Schema)
+		if err != nil {
+			t.Fatal(err)
+		}
+		internalSchema := &apiextensions.JSONSchemaProps{}
+		err = apiextensionsv1beta1.Convert_v1beta1_JSONSchemaProps_To_apiextensions_JSONSchemaProps(v1beta1Schema, internalSchema, nil)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !reflect.DeepEqual(origSchema, internalSchema) {
+			t.Fatalf("original and result differ: %v", diff.ObjectDiff(origSchema, internalSchema))
+		}
+	}
+}