diff --git a/api/filters/annotations/annotations_test.go b/api/filters/annotations/annotations_test.go
index 39fd8e2e2..d52cd673a 100644
--- a/api/filters/annotations/annotations_test.go
+++ b/api/filters/annotations/annotations_test.go
@@ -16,32 +16,15 @@ import (
 
 var annosFs = builtinconfig.MakeDefaultConfig().CommonAnnotations
 
-type setEntryArg struct {
-	Key      string
-	Value    string
-	Tag      string
-	NodePath []string
-}
-
-var setEntryArgs []setEntryArg
-
-func setEntryCallbackStub(key, value, tag string, node *yaml.RNode) {
-	setEntryArgs = append(setEntryArgs, setEntryArg{
-		Key:      key,
-		Value:    value,
-		Tag:      tag,
-		NodePath: node.FieldPath(),
-	})
-}
-
 func TestAnnotations_Filter(t *testing.T) {
+	mutationTrackStub := filtertest_test.MutationTrackerStub{}
 	testCases := map[string]struct {
 		input                string
 		expectedOutput       string
 		filter               Filter
 		fsslice              types.FsSlice
 		setEntryCallback     func(key, value, tag string, node *yaml.RNode)
-		expectedSetEntryArgs []setEntryArg
+		expectedSetEntryArgs []filtertest_test.SetValueArg
 	}{
 		"add": {
 			input: `
@@ -261,14 +244,14 @@ spec:
 					"b": "b1",
 				},
 			},
-			setEntryCallback: setEntryCallbackStub,
+			setEntryCallback: mutationTrackStub.MutationTracker,
 			fsslice: []types.FieldSpec{
 				{
 					Path:               "spec/template/metadata/annotations",
 					CreateIfNotPresent: true,
 				},
 			},
-			expectedSetEntryArgs: []setEntryArg{
+			expectedSetEntryArgs: []filtertest_test.SetValueArg{
 				{
 					Key:      "a",
 					Value:    "a1",
@@ -298,7 +281,7 @@ spec:
 	}
 
 	for tn, tc := range testCases {
-		setEntryArgs = nil
+		mutationTrackStub.Reset()
 		t.Run(tn, func(t *testing.T) {
 			filter := tc.filter
 			filter.WithMutationTracker(tc.setEntryCallback)
@@ -308,7 +291,7 @@ spec:
 				strings.TrimSpace(filtertest_test.RunFilter(t, tc.input, filter))) {
 				t.FailNow()
 			}
-			if !assert.Equal(t, tc.expectedSetEntryArgs, setEntryArgs) {
+			if !assert.Equal(t, tc.expectedSetEntryArgs, mutationTrackStub.SetValueArgs()) {
 				t.FailNow()
 			}
 		})
diff --git a/api/filters/imagetag/imagetag_test.go b/api/filters/imagetag/imagetag_test.go
index a62f95a9f..d1f0bc1de 100644
--- a/api/filters/imagetag/imagetag_test.go
+++ b/api/filters/imagetag/imagetag_test.go
@@ -13,32 +13,15 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
-type setValueArg struct {
-	Key       string
-	Value     string
-	Tag       string
-	PrevValue string
-}
-
-var setValueArgs []setValueArg
-
-func setValueCallbackStub(key, value, tag string, node *yaml.RNode) {
-	setValueArgs = append(setValueArgs, setValueArg{
-		Key:       key,
-		Value:     value,
-		Tag:       tag,
-		PrevValue: node.YNode().Value,
-	})
-}
-
 func TestImageTagUpdater_Filter(t *testing.T) {
+	mutationTrackerStub := filtertest.MutationTrackerStub{}
 	testCases := map[string]struct {
 		input                string
 		expectedOutput       string
 		filter               Filter
 		fsSlice              types.FsSlice
 		setValueCallback     func(key, value, tag string, node *yaml.RNode)
-		expectedSetValueArgs []setValueArg
+		expectedSetValueArgs []filtertest.SetValueArg
 	}{
 		"ignore CustomResourceDefinition": {
 			input: `
@@ -747,30 +730,30 @@ spec:
 					Path: "spec/template/spec/initContainers[]/image",
 				},
 			},
-			setValueCallback: setValueCallbackStub,
-			expectedSetValueArgs: []setValueArg{
+			setValueCallback: mutationTrackerStub.MutationTracker,
+			expectedSetValueArgs: []filtertest.SetValueArg{
 				{
-					Value:     "busybox:v3",
-					PrevValue: "nginx:1.7.9",
+					Value:    "busybox:v3",
+					NodePath: []string{"spec", "template", "spec", "containers", "image"},
 				},
 				{
-					Value:     "busybox:v3",
-					PrevValue: "nginx:latest",
+					Value:    "busybox:v3",
+					NodePath: []string{"spec", "template", "spec", "containers", "image"},
 				},
 				{
-					Value:     "busybox:v3",
-					PrevValue: "nginx",
+					Value:    "busybox:v3",
+					NodePath: []string{"spec", "template", "spec", "initContainers", "image"},
 				},
 				{
-					Value:     "busybox:v3",
-					PrevValue: "nginx@sha256:111111111111111111",
+					Value:    "busybox:v3",
+					NodePath: []string{"spec", "template", "spec", "initContainers", "image"},
 				},
 			},
 		},
 	}
 
 	for tn, tc := range testCases {
-		setValueArgs = nil
+		mutationTrackerStub.Reset()
 		t.Run(tn, func(t *testing.T) {
 			filter := tc.filter
 			filter.WithMutationTracker(tc.setValueCallback)
@@ -780,7 +763,7 @@ spec:
 				strings.TrimSpace(filtertest.RunFilter(t, tc.input, filter))) {
 				t.FailNow()
 			}
-			assert.Equal(t, tc.expectedSetValueArgs, setValueArgs)
+			assert.Equal(t, tc.expectedSetValueArgs, mutationTrackerStub.SetValueArgs())
 		})
 	}
 }
diff --git a/api/filters/labels/labels_test.go b/api/filters/labels/labels_test.go
index 45f4eff4e..0cdb0d126 100644
--- a/api/filters/labels/labels_test.go
+++ b/api/filters/labels/labels_test.go
@@ -14,31 +14,14 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
-type setEntryArg struct {
-	Key      string
-	Value    string
-	Tag      string
-	NodePath []string
-}
-
-var setEntryArgs []setEntryArg
-
-func setEntryCallbackStub(key, value, tag string, node *yaml.RNode) {
-	setEntryArgs = append(setEntryArgs, setEntryArg{
-		Key:      key,
-		Value:    value,
-		Tag:      tag,
-		NodePath: node.FieldPath(),
-	})
-}
-
 func TestLabels_Filter(t *testing.T) {
+	mutationTrackerStub := filtertest_test.MutationTrackerStub{}
 	testCases := map[string]struct {
 		input                string
 		expectedOutput       string
 		filter               Filter
 		setEntryCallback     func(key, value, tag string, node *yaml.RNode)
-		expectedSetEntryArgs []setEntryArg
+		expectedSetEntryArgs []filtertest_test.SetValueArg
 	}{
 		"add": {
 			input: `
@@ -458,8 +441,8 @@ a:
 					},
 				},
 			},
-			setEntryCallback: setEntryCallbackStub,
-			expectedSetEntryArgs: []setEntryArg{
+			setEntryCallback: mutationTrackerStub.MutationTracker,
+			expectedSetEntryArgs: []filtertest_test.SetValueArg{
 				{
 					Key:      "mage",
 					Value:    "yennefer",
@@ -477,7 +460,7 @@ a:
 	}
 
 	for tn, tc := range testCases {
-		setEntryArgs = nil
+		mutationTrackerStub.Reset()
 		t.Run(tn, func(t *testing.T) {
 			tc.filter.WithMutationTracker(tc.setEntryCallback)
 			if !assert.Equal(t,
@@ -485,7 +468,7 @@ a:
 				strings.TrimSpace(filtertest_test.RunFilter(t, tc.input, tc.filter))) {
 				t.FailNow()
 			}
-			if !assert.Equal(t, tc.expectedSetEntryArgs, setEntryArgs) {
+			if !assert.Equal(t, tc.expectedSetEntryArgs, mutationTrackerStub.SetValueArgs()) {
 				t.FailNow()
 			}
 		})
diff --git a/api/testutils/filtertest/runfilter.go b/api/testutils/filtertest/runfilter.go
index 2cf775311..95f8d26c3 100644
--- a/api/testutils/filtertest/runfilter.go
+++ b/api/testutils/filtertest/runfilter.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
 func run(input string, f kio.Filter) (string, error) {
@@ -46,3 +47,32 @@ func RunFilterE(t *testing.T, input string, f kio.Filter) (string, error) {
 	}
 	return output, nil
 }
+
+type SetValueArg struct {
+	Key      string
+	Value    string
+	Tag      string
+	NodePath []string
+}
+
+// MutationTrackerStub to help stub a mutation tracker for kio.TrackableFilter
+type MutationTrackerStub struct {
+	setValueArgs []SetValueArg
+}
+
+func (mts *MutationTrackerStub) MutationTracker(key, value, tag string, node *yaml.RNode) {
+	mts.setValueArgs = append(mts.setValueArgs, SetValueArg{
+		Key:      key,
+		Value:    value,
+		Tag:      tag,
+		NodePath: node.FieldPath(),
+	})
+}
+
+func (mts *MutationTrackerStub) SetValueArgs() []SetValueArg {
+	return mts.setValueArgs
+}
+
+func (mts *MutationTrackerStub) Reset() {
+	mts.setValueArgs = nil
+}