diff --git a/pkg/api/defaulting_test.go b/pkg/api/defaulting_test.go
new file mode 100644
index 00000000000..77144b8da97
--- /dev/null
+++ b/pkg/api/defaulting_test.go
@@ -0,0 +1,124 @@
+/*
+Copyright 2015 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 api_test
+
+import (
+	"math/rand"
+	"reflect"
+	"sort"
+	"testing"
+
+	"github.com/google/gofuzz"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	apiv1 "k8s.io/kubernetes/pkg/api/v1"
+	extensionsv1beta1 "k8s.io/kubernetes/pkg/apis/extensions/v1beta1"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/util/diff"
+)
+
+type orderedGroupVersionKinds []unversioned.GroupVersionKind
+
+func (o orderedGroupVersionKinds) Len() int      { return len(o) }
+func (o orderedGroupVersionKinds) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
+func (o orderedGroupVersionKinds) Less(i, j int) bool {
+	return o[i].String() < o[j].String()
+}
+
+// TODO: add a reflexive test that verifies that all SetDefaults functions are registered
+
+// TODO: once we remove defaulting from conversion, convert this test to ensuring
+// that all objects that say they have defaulting are verified to mutate the originating
+// object.
+func TestDefaulting(t *testing.T) {
+	f := fuzz.New().NilChance(.5).NumElements(1, 1)
+	f.RandSource(rand.NewSource(1))
+	f.Funcs(
+		func(s *runtime.RawExtension, c fuzz.Continue) {},
+		func(s *unversioned.LabelSelector, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			s.MatchExpressions = nil // need to fuzz this specially
+		},
+		func(s *apiv1.ListOptions, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			s.LabelSelector = "" // need to fuzz requirement strings specially
+			s.FieldSelector = "" // need to fuzz requirement strings specially
+		},
+		// No longer necessary when we remove defaulting from conversion
+		func(s *apiv1.Secret, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			s.StringData = nil // is mapped into Data, which cannot easily be tested
+		},
+		func(s *extensionsv1beta1.ListOptions, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			s.LabelSelector = "" // need to fuzz requirement strings specially
+			s.FieldSelector = "" // need to fuzz requirement strings specially
+		},
+		func(s *extensionsv1beta1.ScaleStatus, c fuzz.Continue) {
+			c.FuzzNoCustom(s)
+			s.TargetSelector = "" // need to fuzz requirement strings specially
+		},
+	)
+
+	scheme := api.Scheme
+	var testTypes orderedGroupVersionKinds
+	for gvk := range scheme.AllKnownTypes() {
+		if gvk.Version == runtime.APIVersionInternal {
+			continue
+		}
+		testTypes = append(testTypes, gvk)
+	}
+	sort.Sort(testTypes)
+
+	for _, gvk := range testTypes {
+		for i := 0; i < *fuzzIters; i++ {
+			src, err := scheme.New(gvk)
+			if err != nil {
+				t.Fatal(err)
+			}
+			f.Fuzz(src)
+
+			src.GetObjectKind().SetGroupVersionKind(unversioned.GroupVersionKind{})
+
+			original, _ := scheme.DeepCopy(src)
+
+			// get internal
+			copied, _ := scheme.DeepCopy(src)
+			scheme.Default(copied.(runtime.Object))
+
+			// get expected
+			// TODO: this relies on the side effect behavior of defaulters applying to the external
+			// object
+			if _, err = scheme.UnsafeConvertToVersion(src, runtime.InternalGroupVersioner); err != nil {
+				t.Errorf("[%v] unable to convert: %v", gvk, err)
+				continue
+			}
+			src.GetObjectKind().SetGroupVersionKind(unversioned.GroupVersionKind{})
+
+			existingChanged := !reflect.DeepEqual(original, src)
+			newChanged := !reflect.DeepEqual(original, copied)
+			if existingChanged != newChanged {
+				t.Errorf("[%v] mismatched changes: old=%t new=%t", gvk, existingChanged, newChanged)
+			}
+
+			if !reflect.DeepEqual(src, copied) {
+				t.Errorf("[%v] changed: %s", gvk, diff.ObjectReflectDiff(src, copied))
+			}
+		}
+	}
+}