feat: replacing bytes.Buffer instances used only to generate strings with strings.Builder.

internal/color/color.go

@@ -7,7 +7,6 @@
 package color
 
 import (
-	"bytes"
 	"fmt"
 	"os"
 	"reflect"
@@ -182,13 +181,13 @@ func FromEnv(env, defaultColor string) (string, string, string) {
 }
 
 // AppendTestNameOn enables test name color in b.
-func AppendTestNameOn(b *bytes.Buffer) {
+func AppendTestNameOn(b *strings.Builder) {
 	Init()
 	b.WriteString(TestNameOn)
 }
 
 // AppendTestNameOff disables test name color in b.
-func AppendTestNameOff(b *bytes.Buffer) {
+func AppendTestNameOff(b *strings.Builder) {
 	Init()
 	b.WriteString(TestNameOff)
 }
@@ -211,7 +210,7 @@ func Bad(s string, args ...any) string {
 func BadUsage(usage string, param any, pos int, kind bool) string {
 	Init()
 
-	var b bytes.Buffer
+	var b strings.Builder
 	fmt.Fprintf(&b, "%susage: %s, but received ", BadOnBold, usage)
 
 	if param == nil {

internal/color/color_test.go

@@ -7,8 +7,8 @@
 package color_test
 
 import (
-	"bytes"
 	"os"
+	"strings"
 	"testing"
 
 	"github.com/maxatome/go-testdeep/internal/color"
@@ -27,7 +27,7 @@ func TestColor(t *testing.T) {
 		test.EqualStr(t, bold, "")
 		test.EqualStr(t, off, "")
 
-		var b bytes.Buffer
+		var b strings.Builder
 		color.AppendTestNameOn(&b)
 		test.EqualInt(t, b.Len(), 0)
 		color.AppendTestNameOff(&b)
@@ -77,7 +77,7 @@ func TestColor(t *testing.T) {
 
 		// Color test name
 		_, color.TestNameOn, color.TestNameOff = color.FromEnv(color.EnvColorTitle, "yellow")
-		var b bytes.Buffer
+		var b strings.Builder
 		color.AppendTestNameOn(&b)
 		test.EqualStr(t, b.String(), "\x1b[1;33m")
 		color.AppendTestNameOff(&b)

internal/ctxerr/error.go

@@ -7,7 +7,6 @@
 package ctxerr
 
 import (
-	"bytes"
 	"reflect"
 	"strings"
 
@@ -92,7 +91,7 @@ func TypeMismatch(got, expected reflect.Type) *Error {
 
 // Error implements error interface.
 func (e *Error) Error() string {
-	buf := bytes.Buffer{}
+	buf := strings.Builder{}
 
 	e.Append(&buf, "")
 
@@ -101,7 +100,7 @@ func (e *Error) Error() string {
 
 // Append appends the a contents to buf using prefix prefix for each
 // line.
-func (e *Error) Append(buf *bytes.Buffer, prefix string) {
+func (e *Error) Append(buf *strings.Builder, prefix string) {
 	if e == BooleanError {
 		return
 	}
@@ -209,7 +208,7 @@ func (e *Error) SummaryString() string {
 		return ""
 	}
 
-	var buf bytes.Buffer
+	var buf strings.Builder
 	e.Summary.AppendSummary(&buf, "")
 	return buf.String()
 }

internal/ctxerr/summary.go

@@ -7,7 +7,6 @@
 package ctxerr
 
 import (
-	"bytes"
 	"strings"
 
 	"github.com/maxatome/go-testdeep/internal/color"
@@ -17,7 +16,7 @@ import (
 // ErrorSummary is the interface used to render error summaries. See
 // Error.Summary.
 type ErrorSummary interface {
-	AppendSummary(buf *bytes.Buffer, prefix string)
+	AppendSummary(buf *strings.Builder, prefix string)
 }
 
 // ErrorSummaryItem implements the [ErrorSummary] interface and allows
@@ -40,7 +39,7 @@ type ErrorSummaryItem struct {
 var _ ErrorSummary = ErrorSummaryItem{}
 
 // AppendSummary implements the [ErrorSummary] interface.
-func (s ErrorSummaryItem) AppendSummary(buf *bytes.Buffer, prefix string) {
+func (s ErrorSummaryItem) AppendSummary(buf *strings.Builder, prefix string) {
 	color.Init()
 
 	buf.WriteString(prefix)
@@ -72,7 +71,7 @@ type ErrorSummaryItems []ErrorSummaryItem
 var _ ErrorSummary = (ErrorSummaryItems)(nil)
 
 // AppendSummary implements [ErrorSummary] interface.
-func (s ErrorSummaryItems) AppendSummary(buf *bytes.Buffer, prefix string) {
+func (s ErrorSummaryItems) AppendSummary(buf *strings.Builder, prefix string) {
 	maxLen := 0
 	for _, item := range s {
 		if len(item.Label) > maxLen {
@@ -95,7 +94,7 @@ type errorSummaryString string
 
 var _ ErrorSummary = errorSummaryString("")
 
-func (s errorSummaryString) AppendSummary(buf *bytes.Buffer, prefix string) {
+func (s errorSummaryString) AppendSummary(buf *strings.Builder, prefix string) {
 	color.Init()
 
 	buf.WriteString(prefix)

internal/ctxerr/summary_test.go

@@ -7,7 +7,6 @@
 package ctxerr_test
 
 import (
-	"bytes"
 	"strings"
 	"testing"
 
@@ -17,7 +16,7 @@ import (
 )
 
 func errorSummaryToString(s ctxerr.ErrorSummary, prefix string) string {
-	var buf bytes.Buffer
+	var buf strings.Builder
 	s.AppendSummary(&buf, prefix)
 	return buf.String()
 }

internal/json/lex.go

@@ -264,14 +264,15 @@ func hex(b []byte) (rune, bool) {
 func (j *json) parseString() (string, bool) {
 	// j.buf[j.pos.bpos] == '"' → caller responsibility
 
-	var b *bytes.Buffer
+	var b *strings.Builder
 
 	from := j.pos.bpos + 1
 	savePos := j.pos
 
 	appendBuffer := func(r rune) {
 		if b == nil {
-			b = bytes.NewBuffer(j.buf[from : j.pos.bpos-1])
+			b = &strings.Builder{}
+			b.Write(j.buf[from : j.pos.bpos-1])
 		}
 		b.WriteRune(r)
 	}

internal/util/string.go

@@ -33,8 +33,8 @@ func ToString(val any) string {
 		}
 
 	case []reflect.Value:
-		var buf bytes.Buffer
-		SliceToBuffer(&buf, tval)
+		var buf strings.Builder
+		SliceToString(&buf, tval)
 		return buf.String()
 
 		// no "(string) " prefix for printable strings
@@ -79,26 +79,24 @@ func IndentStringIn(w io.Writer, str, indent, colOn, colOff string) {
 	repl.WriteString(w, str) //nolint: errcheck
 }
 
-// SliceToBuffer stringifies items slice into buf then returns buf.
-func SliceToBuffer(buf *bytes.Buffer, items []reflect.Value) *bytes.Buffer {
+// SliceToString stringifies items slice into buf then returns buf.
+func SliceToString(buf *strings.Builder, items []reflect.Value) *strings.Builder {
 	buf.WriteByte('(')
 
-	begLine := bytes.LastIndexByte(buf.Bytes(), '\n') + 1
+	begLine := strings.LastIndexByte(buf.String(), '\n') + 1
 	prefix := strings.Repeat(" ", buf.Len()-begLine)
 
 	if len(items) < 2 {
 		if len(items) > 0 {
 			buf.WriteString(IndentString(ToString(items[0]), prefix))
 		}
 	} else {
-		for idx, item := range items {
-			if idx != 0 {
-				buf.WriteString(prefix)
-			}
-			buf.WriteString(IndentString(ToString(item), prefix))
+		buf.WriteString(IndentString(ToString(items[0]), prefix))
+		for _, item := range items[1:] {
 			buf.WriteString(",\n")
+			buf.WriteString(prefix)
+			buf.WriteString(IndentString(ToString(item), prefix))
 		}
-		buf.Truncate(buf.Len() - 2)
 	}
 	buf.WriteByte(')')
 

internal/util/string_test.go

@@ -126,8 +126,9 @@ items:
 			}
 		}
 
-		buf := bytes.NewBufferString(curTest.BufInit)
-		test.EqualStr(t, util.SliceToBuffer(buf, items).String(),
+		var buf strings.Builder
+		buf.WriteString(curTest.BufInit)
+		test.EqualStr(t, util.SliceToString(&buf, items).String(),
 			curTest.Expected)
 	}
 }

td/cmp_deeply.go

@@ -7,7 +7,6 @@
 package td
 
 import (
-	"bytes"
 	"reflect"
 	"strings"
 
@@ -119,7 +118,7 @@ func formatError(t TestingT, isFatal bool, err *ctxerr.Error, args ...any) {
 
 	args = flat.Interfaces(args...)
 
-	var buf bytes.Buffer
+	var buf strings.Builder
 	color.AppendTestNameOn(&buf)
 	if len(args) == 0 {
 		buf.WriteString(failedTest)

td/td_list.go

@@ -7,8 +7,8 @@
 package td
 
 import (
-	"bytes"
 	"reflect"
+	"strings"
 
 	"github.com/maxatome/go-testdeep/internal/flat"
 	"github.com/maxatome/go-testdeep/internal/util"
@@ -27,6 +27,8 @@ func newList(items ...any) tdList {
 }
 
 func (l *tdList) String() string {
-	return util.SliceToBuffer(bytes.NewBufferString(l.GetLocation().Func), l.items).
+	var b strings.Builder
+	b.WriteString(l.GetLocation().Func)
+	return util.SliceToString(&b, l.items).
 		String()
 }

td/td_set_base.go

@@ -7,8 +7,8 @@
 package td
 
 import (
-	"bytes"
 	"reflect"
+	"strings"
 
 	"github.com/maxatome/go-testdeep/internal/ctxerr"
 	"github.com/maxatome/go-testdeep/internal/flat"
@@ -162,8 +162,9 @@ func (s *tdSetBase) Match(ctx ctxerr.Context, got reflect.Value) *ctxerr.Error {
 }
 
 func (s *tdSetBase) String() string {
-	return util.SliceToBuffer(
-		bytes.NewBufferString(s.GetLocation().Func), s.expectedItems).String()
+	var b strings.Builder
+	b.WriteString(s.GetLocation().Func)
+	return util.SliceToString(&b, s.expectedItems).String()
 }
 
 func (s *tdSetBase) TypeBehind() reflect.Type {