diff --git a/reconcilers/sync_test.go b/reconcilers/sync_test.go
index d38b823..3a8d7c1 100644
--- a/reconcilers/sync_test.go
+++ b/reconcilers/sync_test.go
@@ -271,3 +271,64 @@ func TestSyncReconciler(t *testing.T) {
 		return rtc.Metadata["SubReconciler"].(func(*testing.T, reconcilers.Config) reconcilers.SubReconciler[*resources.TestResource])(t, c)
 	})
 }
+
+func TestSyncReconcilerDuck(t *testing.T) {
+	testNamespace := "test-namespace"
+	testName := "test-resource"
+
+	scheme := runtime.NewScheme()
+	// _ = resources.AddToScheme(scheme)
+
+	resource := dies.TestDuckBlank.
+		APIVersion(resources.GroupVersion.String()).
+		Kind("TestResource").
+		MetadataDie(func(d *diemetav1.ObjectMetaDie) {
+			d.Namespace(testNamespace)
+			d.Name(testName)
+		}).
+		SpecDie(func(d *dies.TestDuckSpecDie) {
+			d.AddField("mutation", "false")
+		}).
+		StatusDie(func(d *dies.TestResourceStatusDie) {
+			d.ConditionsDie(
+				diemetav1.ConditionBlank.Type(apis.ConditionReady).Status(metav1.ConditionUnknown).Reason("Initializing"),
+			)
+		})
+
+	rts := rtesting.SubReconcilerTests[*resources.TestDuck]{
+		"sync no mutation": {
+			Resource: resource.DieReleasePtr(),
+			Metadata: map[string]interface{}{
+				"SubReconciler": func(t *testing.T, c reconcilers.Config) reconcilers.SubReconciler[*resources.TestDuck] {
+					return &reconcilers.SyncReconciler[*resources.TestDuck]{
+						Sync: func(ctx context.Context, resource *resources.TestDuck) error {
+							return nil
+						},
+					}
+				},
+			},
+		},
+		"sync with mutation": {
+			Resource: resource.DieReleasePtr(),
+			ExpectResource: resource.
+				SpecDie(func(d *dies.TestDuckSpecDie) {
+					d.AddField("mutation", "true")
+				}).
+				DieReleasePtr(),
+			Metadata: map[string]interface{}{
+				"SubReconciler": func(t *testing.T, c reconcilers.Config) reconcilers.SubReconciler[*resources.TestDuck] {
+					return &reconcilers.SyncReconciler[*resources.TestDuck]{
+						Sync: func(ctx context.Context, resource *resources.TestDuck) error {
+							resource.Spec.Fields["mutation"] = "true"
+							return nil
+						},
+					}
+				},
+			},
+		},
+	}
+
+	rts.Run(t, scheme, func(t *testing.T, rtc *rtesting.SubReconcilerTestCase[*resources.TestDuck], c reconcilers.Config) reconcilers.SubReconciler[*resources.TestDuck] {
+		return rtc.Metadata["SubReconciler"].(func(*testing.T, reconcilers.Config) reconcilers.SubReconciler[*resources.TestDuck])(t, c)
+	})
+}
diff --git a/testing/subreconciler.go b/testing/subreconciler.go
index 2c4cc15..d8fac64 100644
--- a/testing/subreconciler.go
+++ b/testing/subreconciler.go
@@ -14,9 +14,11 @@ import (
 	"github.com/go-logr/logr/testr"
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
+	"github.com/vmware-labs/reconciler-runtime/duck"
 	"github.com/vmware-labs/reconciler-runtime/internal"
 	"github.com/vmware-labs/reconciler-runtime/reconcilers"
 	rtime "github.com/vmware-labs/reconciler-runtime/time"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -182,12 +184,22 @@ func (tc *SubReconcilerTestCase[T]) Run(t *testing.T, scheme *runtime.Scheme, fa
 		}()
 	}
 
+	var givenResource client.Object = tc.Resource
+	if duck.IsDuck(givenResource, scheme) {
+		// convert the given resource duck to Unstructured so that it can be created on the fake client
+		uobj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(tc.Resource)
+		if err != nil {
+			t.Fatalf("unable to convert Resource to Unstructured: %s", err)
+		}
+		givenResource = &unstructured.Unstructured{Object: uobj}
+	}
+
 	expectConfig := &ExpectConfig{
 		Name:                    "default",
 		Scheme:                  scheme,
 		StatusSubResourceTypes:  tc.StatusSubResourceTypes,
-		GivenObjects:            append(tc.GivenObjects, tc.Resource),
-		APIGivenObjects:         append(tc.APIGivenObjects, tc.Resource),
+		GivenObjects:            append(tc.GivenObjects, givenResource),
+		APIGivenObjects:         append(tc.APIGivenObjects, givenResource),
 		WithClientBuilder:       tc.WithClientBuilder,
 		WithReactors:            tc.WithReactors,
 		GivenTracks:             tc.GivenTracks,