reencode: Rethink the UTF-8 buffer

1 files changed, 61 insertions, 0 deletions

diff --git a/reencode_test.go b/reencode_test.go
index f135aa5..82a1861 100644
--- a/reencode_test.go
+++ b/reencode_test.go
@@ -161,3 +161,64 @@ func TestReEncode(t *testing.T) {
 		})
 	}
 }
+
+func TestReEncodeWriteSize(t *testing.T) {
+	t.Parallel()
+
+	multibyteRune := `😂`
+	assert.Len(t, multibyteRune, 4)
+
+	input := `"` + multibyteRune + `"`
+
+	t.Run("bytes-bigwrite", func(t *testing.T) {
+		t.Parallel()
+		var out strings.Builder
+		enc := NewReEncoder(&out, ReEncoderConfig{})
+
+		n, err := enc.Write([]byte(input))
+		assert.NoError(t, err)
+		assert.Equal(t, len(input), n)
+
+		assert.Equal(t, input, out.String())
+	})
+	t.Run("string-bigwrite", func(t *testing.T) {
+		t.Parallel()
+		var out strings.Builder
+		enc := NewReEncoder(&out, ReEncoderConfig{})
+
+		n, err := enc.WriteString(input)
+		assert.NoError(t, err)
+		assert.Equal(t, len(input), n)
+
+		assert.Equal(t, input, out.String())
+	})
+
+	t.Run("bytes-smallwrites", func(t *testing.T) {
+		t.Parallel()
+		var out strings.Builder
+		enc := NewReEncoder(&out, ReEncoderConfig{})
+
+		var buf [1]byte
+		for i := 0; i < len(input); i++ {
+			buf[0] = input[i]
+			n, err := enc.Write(buf[:])
+			assert.NoError(t, err)
+			assert.Equal(t, 1, n)
+		}
+
+		assert.Equal(t, input, out.String())
+	})
+	t.Run("string-smallwrites", func(t *testing.T) {
+		t.Parallel()
+		var out strings.Builder
+		enc := NewReEncoder(&out, ReEncoderConfig{})
+
+		for i := 0; i < len(input); i++ {
+			n, err := enc.WriteString(input[i : i+1])
+			assert.NoError(t, err)
+			assert.Equal(t, 1, n)
+		}
+
+		assert.Equal(t, input, out.String())
+	})
+}