diff --git a/mtimes/mtimes_test.go b/mtimes/mtimes_test.go
index f97311a..3a30a5b 100644
--- a/mtimes/mtimes_test.go
+++ b/mtimes/mtimes_test.go
@@ -9,8 +9,8 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"strings"
 	"testing"
+	"text/template"
 	"time"
 
 	"github.com/dmikusa/rust-cargo-cnb/mtimes"
@@ -21,8 +21,9 @@ import (
 
 func testMTimes(t *testing.T, context spec.G, it spec.S) {
 	var (
-		Expect  = NewWithT(t).Expect
-		workDir string
+		Expect         = NewWithT(t).Expect
+		workDir        string
+		mtimesTemplate *template.Template
 	)
 
 	it.Before(func() {
@@ -31,6 +32,9 @@ func testMTimes(t *testing.T, context spec.G, it spec.S) {
 		workDir, err = ioutil.TempDir("", "mtimes-test")
 		Expect(err).NotTo(HaveOccurred())
 
+		mtimesTemplate, err = template.New("mtimes.json").ParseFiles("testdata/mtimes.json")
+		Expect(err).ToNot(HaveOccurred())
+
 		// set up expected files
 		Expect(touch(filepath.Join(workDir, "testdata/folder1/file1a.txt"))).ToNot(HaveOccurred())
 		Expect(touch(filepath.Join(workDir, "testdata/folder1/file1b.txt"))).ToNot(HaveOccurred())
@@ -107,10 +111,10 @@ func testMTimes(t *testing.T, context spec.G, it spec.S) {
 			Expect(filepath.Join(workDir, "testdata", "folder1")).To(HaveMTime(originTime))
 
 			// copy test mtimes.json file
-			data, err := ioutil.ReadFile("testdata/mtimes.json")
+			var b bytes.Buffer
+			err := mtimesTemplate.Execute(&b, map[string]string{"WorkDir": workDir})
 			Expect(err).ToNot(HaveOccurred())
-			data = []byte(strings.ReplaceAll(string(data), "##workdir##", workDir))
-			err = ioutil.WriteFile(filepath.Join(workDir, "testdata/mtimes.json"), data, 0644)
+			err = ioutil.WriteFile(filepath.Join(workDir, "testdata/mtimes.json"), b.Bytes(), 0644)
 			Expect(err).ToNot(HaveOccurred())
 
 			preserver := mtimes.NewPreserver(scribe.NewEmitter(&logs))
diff --git a/mtimes/testdata/mtimes.json b/mtimes/testdata/mtimes.json
index e526c04..ddf707f 100644
--- a/mtimes/testdata/mtimes.json
+++ b/mtimes/testdata/mtimes.json
@@ -1,17 +1,17 @@
-{"Path":"##workdir##/testdata","MTime":"2021-04-13T21:32:42.266625461Z"}
-{"Path":"##workdir##/testdata/folder1","MTime":"2021-04-13T21:32:16.56220856Z"}
-{"Path":"##workdir##/testdata/folder1/file1a.txt","MTime":"2021-04-13T21:32:11.619000841Z"}
-{"Path":"##workdir##/testdata/folder1/file1b.txt","MTime":"2021-04-13T21:32:16.562185855Z"}
-{"Path":"##workdir##/testdata/folder1/folder2","MTime":"2021-04-13T21:33:12.836115365Z"}
-{"Path":"##workdir##/testdata/folder1/folder2/file2a.txt","MTime":"2021-04-13T21:32:24.132Z"}
-{"Path":"##workdir##/testdata/folder1/folder2/file2b.txt","MTime":"2021-04-13T21:33:12.836100946Z"}
-{"Path":"##workdir##/testdata/folder1/folder2/folder3","MTime":"2021-04-13T21:33:24.454010729Z"}
-{"Path":"##workdir##/testdata/folder1/folder2/folder3/file3a.txt","MTime":"2021-04-13T21:33:21.115193516Z"}
-{"Path":"##workdir##/testdata/folder1/folder2/folder3/file3b.txt","MTime":"2021-04-17T23:20:26.337053Z"}
-{"Path":"##workdir##/testdata/foldera","MTime":"2021-04-13T21:31:49.712696151Z"}
-{"Path":"##workdir##/testdata/foldera/filea1.txt","MTime":"2021-04-13T21:31:44.719991295Z"}
-{"Path":"##workdir##/testdata/foldera/filea2.txt","MTime":"2021-04-13T21:31:49.712681414Z"}
-{"Path":"##workdir##/testdata/foldera/folderb","MTime":"2021-04-13T21:31:36.645595542Z"}
-{"Path":"##workdir##/testdata/foldera/folderb/fileb1.txt","MTime":"2021-04-13T21:31:36.645581261Z"}
-{"Path":"##workdir##/testdata/foldera/folderb/folderc","MTime":"2021-04-13T21:31:27.300292894Z"}
-{"Path":"##workdir##/testdata/foldera/folderb/folderc/filec1.txt","MTime":"2021-04-13T21:31:27.30028183Z"}
\ No newline at end of file
+{"Path":"{{.WorkDir}}/testdata","MTime":"2021-04-13T21:32:42.266625461Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1","MTime":"2021-04-13T21:32:16.56220856Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/file1a.txt","MTime":"2021-04-13T21:32:11.619000841Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/file1b.txt","MTime":"2021-04-13T21:32:16.562185855Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/folder2","MTime":"2021-04-13T21:33:12.836115365Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/folder2/file2a.txt","MTime":"2021-04-13T21:32:24.132Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/folder2/file2b.txt","MTime":"2021-04-13T21:33:12.836100946Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/folder2/folder3","MTime":"2021-04-13T21:33:24.454010729Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/folder2/folder3/file3a.txt","MTime":"2021-04-13T21:33:21.115193516Z"}
+{"Path":"{{.WorkDir}}/testdata/folder1/folder2/folder3/file3b.txt","MTime":"2021-04-17T23:20:26.337053Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera","MTime":"2021-04-13T21:31:49.712696151Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera/filea1.txt","MTime":"2021-04-13T21:31:44.719991295Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera/filea2.txt","MTime":"2021-04-13T21:31:49.712681414Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera/folderb","MTime":"2021-04-13T21:31:36.645595542Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera/folderb/fileb1.txt","MTime":"2021-04-13T21:31:36.645581261Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera/folderb/folderc","MTime":"2021-04-13T21:31:27.300292894Z"}
+{"Path":"{{.WorkDir}}/testdata/foldera/folderb/folderc/filec1.txt","MTime":"2021-04-13T21:31:27.30028183Z"}
\ No newline at end of file