test: reproduce integer key marshal failure

api/krusty/configmaps_test.go

@@ -9,6 +9,31 @@ import (
 	kusttest_test "sigs.k8s.io/kustomize/api/testutils/kusttest"
 )
 
+func TestIntegerKey(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK(".", `
+resources:
+- cm.yaml
+`)
+	th.WriteF("cm.yaml", `
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: cm
+data:
+  123: abc
+`)
+	m := th.Run(".", th.MakeDefaultOptions())
+	th.AssertActualEqualsExpected(m, `
+apiVersion: v1
+data:
+  "123": abc
+kind: ConfigMap
+metadata:
+  name: cm
+`)
+}
+
 // Numbers and booleans are quoted
 func TestGeneratorIntVsStringNoMerge(t *testing.T) {
 	th := kusttest_test.MakeHarness(t)