chore: add buffer unit tests (#7453)

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

pkg/engine/mutate/patch/buffer.go

@@ -1,6 +1,8 @@
 package patch
 
-import "bytes"
+import (
+	"bytes"
+)
 
 // buffer is a wrapper around a slice of bytes used for JSON
 // marshal and unmarshal operations for a strategic merge patch
@@ -11,7 +13,6 @@ type buffer struct {
 // UnmarshalJSON writes the slice of bytes to an internal buffer
 func (buff buffer) UnmarshalJSON(b []byte) error {
 	buff.Reset()
-
 	if _, err := buff.Write(b); err != nil {
 		return err
 	}

pkg/engine/mutate/patch/buffer_test.go

@@ -0,0 +1,56 @@
+package patch
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+)
+
+func Test_buffer_UnmarshalJSON(t *testing.T) {
+	tests := []struct {
+		name    string
+		Buffer  *bytes.Buffer
+		b       []byte
+		wantErr bool
+	}{{
+		Buffer: bytes.NewBufferString(""),
+		b:      []byte("aaa"),
+	}}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buff := buffer{
+				Buffer: tt.Buffer,
+			}
+			if err := buff.UnmarshalJSON(tt.b); (err != nil) != tt.wantErr {
+				t.Errorf("buffer.UnmarshalJSON() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func Test_buffer_MarshalJSON(t *testing.T) {
+	tests := []struct {
+		name    string
+		Buffer  *bytes.Buffer
+		want    []byte
+		wantErr bool
+	}{{
+		Buffer: bytes.NewBufferString("aaa"),
+		want:   []byte("aaa"),
+	}}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buff := buffer{
+				Buffer: tt.Buffer,
+			}
+			got, err := buff.MarshalJSON()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("buffer.MarshalJSON() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("buffer.MarshalJSON() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}