diff --git a/core/mapping/utils_test.go b/core/mapping/utils_test.go
index 8a864589..85b27c42 100644
--- a/core/mapping/utils_test.go
+++ b/core/mapping/utils_test.go
@@ -209,6 +209,12 @@ func TestRepr(t *testing.T) {
 			newMockPtr(),
 			"mockptr",
 		},
+		{
+			&mockOpacity{
+				val: 1,
+			},
+			"{1}",
+		},
 		{
 			true,
 			"true",
diff --git a/core/mapping/yamlunmarshaler_test.go b/core/mapping/yamlunmarshaler_test.go
index d635fd74..e0224d6f 100644
--- a/core/mapping/yamlunmarshaler_test.go
+++ b/core/mapping/yamlunmarshaler_test.go
@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"k8s.io/utils/io"
 )
 
 func TestUnmarshalYamlBytes(t *testing.T) {
@@ -18,6 +19,22 @@ func TestUnmarshalYamlBytes(t *testing.T) {
 	assert.Equal(t, "liao", c.Name)
 }
 
+func TestUnmarshalYamlBytesErrorInput(t *testing.T) {
+	var c struct {
+		Name string
+	}
+	content := []byte(`liao`)
+	assert.NotNil(t, UnmarshalYamlBytes(content, &c))
+}
+
+func TestUnmarshalYamlBytesEmptyInput(t *testing.T) {
+	var c struct {
+		Name string
+	}
+	content := []byte(``)
+	assert.NotNil(t, UnmarshalYamlBytes(content, &c))
+}
+
 func TestUnmarshalYamlBytesOptional(t *testing.T) {
 	var c struct {
 		Name string
@@ -918,3 +935,18 @@ func TestUnmarshalYamlReaderError(t *testing.T) {
 	err := UnmarshalYamlReader(reader, &v)
 	assert.NotNil(t, err)
 }
+
+func TestUnmarshalYamlBadReader(t *testing.T) {
+	var v struct {
+		Any string
+	}
+
+	err := UnmarshalYamlReader(new(badReader), &v)
+	assert.NotNil(t, err)
+}
+
+type badReader struct{}
+
+func (b *badReader) Read(p []byte) (n int, err error) {
+	return 0, io.ErrLimitReached
+}