init

.drone.yml

@@ -0,0 +1,15 @@
+---
+kind: pipeline
+name: default
+
+steps:
+- name: test 
+  image: golang
+  commands:
+  # - go test -parallel 10 -race ./... 
+  - go test ./... 
+
+- name: golangci-lint
+  image: golangci/golangci-lint:v1.61
+  commands:
+  - golangci-lint run

.golangci.yml

@@ -0,0 +1,50 @@
+linters-settings:
+    dupl:
+      threshold: 100
+    funlen:
+      lines: 100
+      statements: 60
+    goconst:
+      min-len: 2
+      min-occurrences: 2
+    gocyclo:
+      min-complexity: 15
+    golint:
+      min-confidence: 0
+    lll:
+      line-length: 140
+    maligned:
+      suggest-new: true
+    misspell:
+      locale: US  
+    varnamelen:
+      min-name-length: 2
+      ignore-decls:
+        - w io.Writer
+        - t testing.T
+        - e error
+        - i int
+        - b bytes.Buffer
+        - h Handle
+
+linters:
+    enable-all: true
+    disable:
+      - gochecknoglobals
+      - ireturn
+      - mnd
+      - nolintlint
+      # deprecated
+      - gomnd
+      - exportloopref
+      - execinquery
+
+issues:
+  # Excluding configuration per-path, per-linter, per-text and per-source
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - gochecknoglobals
+        - depguard
+        - gosec
+        - errchkjson

example_test.go

@@ -0,0 +1,76 @@
+package bytesize_test
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"gitoa.ru/go-4devs/bytesize"
+)
+
+func ExampleParse() {
+	size, err := bytesize.Parse("100kB")
+	fmt.Printf("100kB:%[1]T(%[1]d),%[2]v\n", size, err)
+
+	size, err = bytesize.Parse("100PB")
+	fmt.Printf("100PB:%[1]T(%[1]d),%[2]v\n", size, err)
+
+	size, err = bytesize.Parse("100KiB")
+	fmt.Printf("100PB:%[1]T(%[1]d),%[2]v\n", size, err)
+
+	size, err = bytesize.Parse("100MiB")
+	fmt.Printf("100PB:%[1]T(%[1]d),%[2]v\n", size, err)
+
+	size, err = bytesize.Parse("100B")
+	fmt.Printf("100PB:%[1]T(%[1]d),%[2]v\n", size, err)
+
+	// Output:
+	// 100kB:bytesize.Size(100000),<nil>
+	// 100PB:bytesize.Size(100000000000000000),<nil>
+	// 100PB:bytesize.Size(102400),<nil>
+	// 100PB:bytesize.Size(104857600),<nil>
+	// 100PB:bytesize.Size(100),<nil>
+}
+
+func ExampleSize_String() {
+	fmt.Printf("%[1]T(%[1]d) = %[1]s\n", bytesize.Size(100000))
+	fmt.Printf("%[1]T(%[1]d) = %[1]s\n", bytesize.Size(100000000000000000))
+	fmt.Printf("%[1]T(%[1]d) = %[1]s\n", bytesize.Size(102400))
+	fmt.Printf("%[1]T(%[1]d) = %[1]s\n", bytesize.Size(104857600))
+	fmt.Printf("%[1]T(%[1]d) = %[1]s\n", bytesize.Size(100))
+
+	// Output:
+	// bytesize.Size(100000) = 100kB
+	// bytesize.Size(100000000000000000) = 100PB
+	// bytesize.Size(102400) = 102.4kB
+	// bytesize.Size(104857600) = 104.8576MB
+	// bytesize.Size(100) = 100B
+}
+
+func ExampleSize_jsonMarshal() {
+	size := bytesize.Size(100000)
+	data, _ := json.Marshal(size)
+	fmt.Printf("%[1]T(%[1]d) = %[2]s\n", size, data)
+
+	size = bytesize.Size(100000000000000000)
+	data, _ = json.Marshal(size)
+	fmt.Printf("%[1]T(%[1]d) = %[2]s\n", size, data)
+
+	size = bytesize.Size(102400)
+	data, _ = json.Marshal(size)
+	fmt.Printf("%[1]T(%[1]d) = %[2]s\n", size, data)
+
+	size = bytesize.Size(104857600)
+	data, _ = json.Marshal(size)
+	fmt.Printf("%[1]T(%[1]d) = %[2]s\n", size, data)
+
+	size = bytesize.Size(100)
+	data, _ = json.Marshal(size)
+	fmt.Printf("%[1]T(%[1]d) = %[2]s\n", size, data)
+
+	// Output:
+	// bytesize.Size(100000) = "100kB"
+	// bytesize.Size(100000000000000000) = "100PB"
+	// bytesize.Size(102400) = "102.4kB"
+	// bytesize.Size(104857600) = "104.8576MB"
+	// bytesize.Size(100) = "100B"
+}

go.mod

@@ -0,0 +1,3 @@
+module gitoa.ru/go-4devs/bytesize
+
+go 1.22.5

size.go

@@ -0,0 +1,357 @@
+package bytesize
+
+import (
+	"errors"
+	"fmt"
+)
+
+type Size int64
+
+// Byte size prefix.
+const (
+	Byte     Size = 1                // byte
+	Kibibyte Size = 1 << (10 * iota) // kibibyte
+	Mebibyte                         // mebibyte
+	Gibibyte                         // gibibyte
+	Tebibyte                         // tebibyte
+	Pebibyte                         // pebibyte
+
+	Kilobyte Size = 1000 * Byte     // kilobyte
+	Megabyte Size = 1000 * Kilobyte // megabyte
+	Gigabyte Size = 1000 * Megabyte // gigabyte
+	Terabyte Size = 1000 * Gigabyte // terabyte
+	Petabyte Size = 1000 * Terabyte // petabyte
+)
+
+var unitMap = map[string]uint64{
+	"B":   uint64(Byte),
+	"KiB": uint64(Kibibyte),
+	"MiB": uint64(Mebibyte),
+	"GiB": uint64(Gibibyte),
+	"TiB": uint64(Tebibyte),
+	"PiB": uint64(Pebibyte),
+
+	"kB": uint64(Kilobyte),
+	"KB": uint64(Kilobyte),
+	"MB": uint64(Megabyte),
+	"GB": uint64(Gigabyte),
+	"TB": uint64(Terabyte),
+	"PB": uint64(Petabyte),
+}
+
+var (
+	ErrInvalidSize = errors.New("bytesize: invalid size")
+	ErrMissingUnit = errors.New("bytesize: missing unit")
+	ErrUnknownUnit = errors.New("bytesize: unknown unit")
+)
+
+// Parse parses a size string.
+// A byte size string is a possibly signed sequence of
+// decimal numbers, each with optional fraction and a unit suffix,
+// such as "300kB", "-1.5GiB" or "2GB45MB".
+// Valid units are "B", "KiB", "MiB", "GiB", "TiB", "PiB" for binary size.
+// Valid units are "B", "kB", "MB", "GB", "TB", "PB" for human size.
+//
+// nolint: funlen,gocognit,gocyclo,cyclop
+func Parse(in string) (Size, error) {
+	// [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+
+	orig := in
+	neg := false
+
+	var res uint64
+
+	// Consume [-+]?
+	if in != "" {
+		c := in[0]
+		if c == '-' || c == '+' {
+			neg = c == '-'
+			in = in[1:]
+		}
+	}
+	// Special case: if all that is left is "0", this is zero.
+	if in == "0" {
+		return 0, nil
+	}
+
+	if in == "" {
+		return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+	}
+
+	for in != "" {
+		var (
+			val, fVal uint64      // integers before, after decimal point
+			scale     float64 = 1 // value = v + f/scale
+		)
+
+		var err error
+
+		// The next character must be [0-9.]
+		if !(in[0] == '.' || '0' <= in[0] && in[0] <= '9') {
+			return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+		}
+
+		// Consume [0-9]*
+		pl := len(in)
+
+		val, in, err = leadingInt(in)
+		if err != nil {
+			return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+		}
+
+		pre := pl != len(in) // whether we consumed anything before a period
+
+		// Consume (\.[0-9]*)?
+		post := false
+
+		if in != "" && in[0] == '.' {
+			in = in[1:]
+			pl := len(in)
+			fVal, scale, in = leadingFraction(in)
+			post = pl != len(in)
+		}
+
+		if !pre && !post {
+			// no digits (e.g. ".s" or "-.s")
+			return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+		}
+
+		// Consume unit.
+		i := 0
+		for ; i < len(in); i++ {
+			c := in[i]
+			if c == '.' || '0' <= c && c <= '9' {
+				break
+			}
+		}
+
+		if i == 0 {
+			return 0, fmt.Errorf("%w %q", ErrMissingUnit, orig)
+		}
+
+		u := in[:i]
+		in = in[i:]
+		unit, ok := unitMap[u]
+
+		if !ok {
+			return 0, fmt.Errorf("%w %s in size %q", ErrMissingUnit, u, orig)
+		}
+
+		if val > 1<<63/unit {
+			// overflow
+			return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+		}
+
+		val *= unit
+		if fVal > 0 {
+			// float64 is needed to be nanosecond accurate for fractions of hours.
+			// v >= 0 && (f*unit/scale) <= 3.6e+12 (ns/h, h is the largest unit)
+			val += uint64(float64(fVal) * (float64(unit) / scale))
+			if val > 1<<63 {
+				// overflow
+				return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+			}
+		}
+
+		res += val
+		if res > 1<<63 {
+			return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+		}
+	}
+
+	if neg {
+		return -Size(res), nil
+	}
+
+	if res > 1<<63-1 {
+		return 0, fmt.Errorf("%w %q", ErrInvalidSize, orig)
+	}
+
+	return Size(res), nil
+}
+
+// leadingFraction consumes the leading [0-9]* from s.
+// It is used only for fractions, so does not return an error on overflow,
+// it just stops accumulating precision.
+func leadingFraction(in string) (uint64, float64, string) {
+	i := 0
+	scale := float64(1)
+	overflow := false
+
+	var res uint64
+
+	for ; i < len(in); i++ {
+		cur := in[i]
+		if cur < '0' || cur > '9' {
+			break
+		}
+
+		if overflow {
+			continue
+		}
+
+		if res > (1<<63-1)/10 {
+			// It's possible for overflow to give a positive number, so take care.
+			overflow = true
+
+			continue
+		}
+
+		pres := res*10 + uint64(cur) - '0'
+		if pres > 1<<63 {
+			overflow = true
+
+			continue
+		}
+
+		res = pres
+		scale *= 10
+	}
+
+	return res, scale, in[i:]
+}
+
+var errLeadingInt = errors.New("bytesize: bad [0-9]*")
+
+// leadingInt consumes the leading [0-9]* from in.
+func leadingInt[bytes []byte | string](in bytes) (uint64, bytes, error) {
+	i := 0
+
+	var (
+		res uint64
+		rem bytes
+	)
+
+	for ; i < len(in); i++ {
+		curr := in[i]
+
+		if curr < '0' || curr > '9' {
+			break
+		}
+
+		if res > 1<<63/10 {
+			// overflow
+			return 0, rem, errLeadingInt
+		}
+
+		res = res*10 + uint64(curr) - '0'
+		if res > 1<<63 {
+			// overflow
+			return 0, rem, errLeadingInt
+		}
+	}
+
+	return res, in[i:], nil
+}
+
+func (s Size) String() string {
+	var arr [32]byte
+	n := s.format(&arr)
+
+	return string(arr[n:])
+}
+
+// format formats the representation of d into the end of buf and
+// returns the offset of the first character.
+// nolint: gosec
+func (s Size) format(buf *[32]byte) int {
+	wLen := len(buf)
+
+	data := uint64(s)
+	neg := s < 0
+
+	if neg {
+		data = -data
+	}
+
+	prec := 3
+	wLen--
+	buf[wLen] = 'B'
+	wLen--
+
+	switch {
+	case data == 0:
+		buf[wLen] = '0'
+
+		return wLen
+	case data < uint64(Kilobyte):
+		// print bytes
+		wLen++
+		prec = 0
+	case data < uint64(Megabyte):
+		// print kipobytes
+		buf[wLen] = 'k'
+	case data < uint64(Gigabyte):
+		// print megabytes
+		prec = 6
+		buf[wLen] = 'M'
+	case data < uint64(Terabyte):
+		// print gigabytes
+		prec = 9
+		buf[wLen] = 'G'
+	case data < uint64(Petabyte):
+		// print terabytes
+		prec = 12
+		buf[wLen] = 'T'
+	default:
+		// print petobytes
+		prec = 15
+		buf[wLen] = 'P'
+	}
+
+	wLen, data = fmtFrac(buf[:wLen], data, prec)
+	wLen = fmtInt(buf[:wLen], data)
+
+	if neg {
+		wLen--
+		buf[wLen] = '-'
+	}
+
+	return wLen
+}
+
+// fmtFrac formats the fraction of v/10**prec (e.g., ".12345") into the
+// tail of buf, omitting trailing zeros. It omits the decimal
+// point too when the fraction is 0. It returns the index where the
+// output bytes begin and the value v/10**prec.
+func fmtFrac(buf []byte, val uint64, prec int) (int, uint64) {
+	// Omit trailing zeros up to and including decimal point.
+	wLen := len(buf)
+	show := false
+
+	for range prec {
+		digit := val % 10
+		show = show || digit != 0
+
+		if show {
+			wLen--
+			buf[wLen] = byte(digit) + '0'
+		}
+
+		val /= 10
+	}
+
+	if show {
+		wLen--
+		buf[wLen] = '.'
+	}
+
+	return wLen, val
+}
+
+// fmtInt formats v into the tail of buf.
+// It returns the index where the output begins.
+func fmtInt(buf []byte, val uint64) int {
+	wLen := len(buf)
+	if val == 0 {
+		wLen--
+		buf[wLen] = '0'
+	} else {
+		for val > 0 {
+			wLen--
+			buf[wLen] = byte(val%10) + '0'
+			val /= 10
+		}
+	}
+
+	return wLen
+}

size_json.go

@@ -0,0 +1,9 @@
+package bytesize
+
+// func (s Size) MarshalJSON() ([]byte, error) {
+// 	return nil, nil
+// }
+
+// func (s *Size) UnmarshalJSON([]byte) error {
+// 	return nil
+// }

size_test.go

@@ -0,0 +1,190 @@
+package bytesize_test
+
+import (
+	"math"
+	"math/rand"
+	"strings"
+	"testing"
+
+	"gitoa.ru/go-4devs/bytesize"
+)
+
+var parseTests = []struct {
+	in   string
+	want bytesize.Size
+}{
+	// simple
+	{"0", 0},
+	{"5KiB", 5 * bytesize.Kibibyte},
+	{"30KiB", 30 * bytesize.Kibibyte},
+	{"1478KiB", 1478 * bytesize.Kibibyte},
+	// sign
+	{"-5KiB", -5 * bytesize.Kibibyte},
+	{"+5KiB", 5 * bytesize.Kibibyte},
+	{"-0", 0},
+	{"+0", 0},
+	// decimal
+	{"5.0KiB", 5 * bytesize.Kibibyte},
+	{"5.6KiB", 5*bytesize.Kibibyte + bytesize.Kibibyte*6/10},
+	{"5.KiB", 5 * bytesize.Kibibyte},
+	{".5KiB", bytesize.Kibibyte / 2},
+	{"1.0KiB", 1 * bytesize.Kibibyte},
+	{"1.00KiB", 1 * bytesize.Kibibyte},
+	{"1.004KiB", 1*bytesize.Kibibyte + 4*bytesize.Byte},
+	{"1.0040KiB", 1*bytesize.Kibibyte + 4*bytesize.Byte},
+	{"100.00100KiB", 100*bytesize.Kibibyte + 1*bytesize.Byte},
+	// different units
+	{"10B", 10 * bytesize.Byte},
+	{"11KiB", 11 * bytesize.Kibibyte},
+	{"12MiB", 12 * bytesize.Mebibyte},
+	{"12GiB", 12 * bytesize.Gibibyte},
+	{"13TiB", 13 * bytesize.Tebibyte},
+	{"14PiB", 14 * bytesize.Pebibyte},
+	// composite durations
+	{"3PiB30TiB", 3*bytesize.Pebibyte + 30*bytesize.Tebibyte},
+	{"10.5MiB4TiB", 4*bytesize.Tebibyte + 10*bytesize.Mebibyte + bytesize.Mebibyte/2},
+	{"-2TiB3.4MiB", -(2*bytesize.Tebibyte + 3*bytesize.Mebibyte + bytesize.Mebibyte*4/10)},
+	{
+		"1PiB2TiB3GiB4MiB5KiB6B",
+		1*bytesize.Pebibyte + 2*bytesize.Tebibyte + 3*bytesize.Gibibyte + 4*bytesize.Mebibyte + 5*bytesize.Kibibyte + 6*bytesize.Byte,
+	},
+	{
+		"39PiB9TiB14.425GiB",
+		39*bytesize.Pebibyte + 9*bytesize.Tebibyte + 14*bytesize.Gibibyte + bytesize.Gibibyte*425/1000,
+	},
+	// large value
+	{"52763797000B", 52763797000 * bytesize.Byte},
+	// more than 9 digits after decimal point
+	{"0.3333333333333333333GiB", bytesize.Gibibyte * 3333333333 / 1e10},
+	// 9007199254740993 = 1<<53+1 cannot be stored precisely in a float64
+	{"9007199254740993B", (1<<53 + 1) * bytesize.Byte},
+	// largest duration that can be represented by int64 in nanoseconds
+	{"9223372036854775807B", (1<<63 - 1) * bytesize.Byte},
+	{"-9223372036854775808B", -1 << 63 * bytesize.Byte},
+	// largest negative value
+	{"-9223372036854775808B", -1 << 63 * bytesize.Byte},
+	{"0.100000000000000000000MiB", bytesize.Mebibyte * 1 / 10},
+
+	// simple
+	{"5GB", 5 * bytesize.Gigabyte},
+	{"30GB", 30 * bytesize.Gigabyte},
+	{"1478GB", 1478 * bytesize.Gigabyte},
+	// sign
+	{"-5GB", -5 * bytesize.Gigabyte},
+	{"+5GB", 5 * bytesize.Gigabyte},
+	// decimal
+	{"5.0GB", 5 * bytesize.Gigabyte},
+	{"5.6GB", 5*bytesize.Gigabyte + 600*bytesize.Megabyte},
+	{"5.GB", 5 * bytesize.Gigabyte},
+	{".5GB", 500 * bytesize.Megabyte},
+	{"1.0GB", 1 * bytesize.Gigabyte},
+	{"1.00GB", 1 * bytesize.Gigabyte},
+	{"1.004GB", 1*bytesize.Gigabyte + 4*bytesize.Megabyte},
+	{"1.0040GB", 1*bytesize.Gigabyte + 4*bytesize.Megabyte},
+	{"100.00100GB", 100*bytesize.Gigabyte + 1*bytesize.Megabyte},
+	// different units
+	{"10B", 10 * bytesize.Byte},
+	{"11kB", 11 * bytesize.Kilobyte},
+	{"12MB", 12 * bytesize.Megabyte},
+	{"12GB", 12 * bytesize.Gigabyte},
+	{"13TB", 13 * bytesize.Terabyte},
+	{"14PB", 14 * bytesize.Petabyte},
+	// composite durations
+	{"3GB30MB", 3*bytesize.Gigabyte + 30*bytesize.Megabyte},
+	{"10.5MB4GB", 4*bytesize.Gigabyte + 10*bytesize.Megabyte + 500*bytesize.Kilobyte},
+	{"-2TB3.4GB", -(2*bytesize.Terabyte + 3*bytesize.Gigabyte + 400*bytesize.Megabyte)},
+	{
+		"1PB2TB3GB4MB5kB6B",
+		1*bytesize.Petabyte + 2*bytesize.Terabyte + 3*bytesize.Gigabyte + 4*bytesize.Megabyte + 5*bytesize.Kilobyte + 6*bytesize.Byte,
+	},
+	{"39PB9TB14.425GB", 39*bytesize.Petabyte + 9*bytesize.Terabyte + 14*bytesize.Gigabyte + 425*bytesize.Megabyte},
+	{"9223372036854775.807kB", (1<<63 - 1) * bytesize.Byte},
+	{"9223372036GB854MB775kB807B", (1<<63 - 1) * bytesize.Byte},
+	{"-9223372036854775.808kB", -1 << 63 * bytesize.Byte},
+	{"-9223372036GB854MB775kB808B", -1 << 63 * bytesize.Byte},
+	// largest negative round trip value
+	{"-9223372036GB854MB775.808kB", -1 << 63 * bytesize.Byte},
+}
+
+func TestParse(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range parseTests {
+		d, err := bytesize.Parse(tc.in)
+		if err != nil || d != tc.want {
+			t.Errorf("Parse(%q) = %v, %v, want %v, nil", tc.in, d, err, tc.want)
+		}
+	}
+}
+
+var parseErrorTests = []struct {
+	in     string
+	expect string
+}{
+	// invalid
+	{"", `""`},
+	{"3", `"3"`},
+	{"-", `"-"`},
+	{"kB", `"kB"`},
+	{".", `"."`},
+	{"-.", `"-."`},
+	{".MB", `".MB"`},
+	{"+.MB", `"+.MB"`},
+	{"1ExB", `"1ExB"`},
+	{"\x85\x85", `"\x85\x85"`},
+	{"\xffff", `"\xffff"`},
+	{"hello \xffff world", `"hello \xffff world"`},
+	{"\uFFFD", `"�"`},                                  // utf8.RuneError
+	{"\uFFFD hello \uFFFD world", `"� hello � world"`}, // utf8.RuneError
+	// overflow
+	{"9223372036854775810B", `"9223372036854775810B"`},
+	{"9223372036854775808B", `"9223372036854775808B"`},
+	{"-9223372036854775809B", `"-9223372036854775809B"`},
+	{"9223372036854776kB", `"9223372036854776kB"`},
+	{"3000000PB", `"3000000PB"`},
+	{"9223372036854775.808KiB", `"9223372036854775.808KiB"`},
+	{"9223372036854MB775kB808B", `"9223372036854MB775kB808B"`},
+}
+
+func TestParseErrors(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range parseErrorTests {
+		_, err := bytesize.Parse(tc.in)
+		if err == nil {
+			t.Errorf("Parse(%q) = _, nil, want _, non-nil", tc.in)
+		} else if !strings.Contains(err.Error(), tc.expect) {
+			t.Errorf("Parse(%q) = _, %q, error does not contain %q", tc.in, err, tc.expect)
+		}
+	}
+}
+
+func TestParseRoundTrip(t *testing.T) {
+	t.Parallel()
+
+	max0 := bytesize.Size(math.MaxInt64)
+	max1, err := bytesize.Parse(max0.String())
+
+	if err != nil || max0 != max1 {
+		t.Errorf("round-trip failed: %d => %q => %d, %v", max0, max0.String(), max1, err)
+	}
+
+	min0 := bytesize.Size(math.MinInt64)
+	min1, err := bytesize.Parse(min0.String())
+
+	if err != nil || min0 != min1 {
+		t.Errorf("round-trip failed: %d => %q => %d, %v", min0, min0.String(), min1, err)
+	}
+
+	for range 100 {
+		// Resolutions finer than milliseconds will result in
+		// imprecise round-trips.
+		d0 := bytesize.Size(rand.Int31()) * bytesize.Megabyte
+		s := d0.String()
+		d1, err := bytesize.Parse(s)
+
+		if err != nil || d0 != d1 {
+			t.Errorf("round-trip failed: %d => %q => %d, %v", d0, s, d1, err)
+		}
+	}
+}

size_text.go

@@ -0,0 +1,20 @@
+package bytesize
+
+import "fmt"
+
+func (s Size) MarshalText() ([]byte, error) {
+	val := s.String()
+
+	return []byte(val), nil
+}
+
+func (s *Size) UnmarshalText(text []byte) error {
+	val, err := Parse(string(text))
+	if err != nil {
+		return fmt.Errorf("%w: unmarshal text", err)
+	}
+
+	*s = val
+
+	return nil
+}

size_text_test.go

@@ -0,0 +1,55 @@
+package bytesize_test
+
+import (
+	"encoding/json"
+	"math"
+	"testing"
+
+	"gitoa.ru/go-4devs/bytesize"
+)
+
+var marshalTextTests = []struct {
+	in     bytesize.Size
+	expect string
+}{
+	{bytesize.Size(0), `"0B"`},
+	{bytesize.Size(100), `"100B"`},
+	{bytesize.Size(1024), `"1.024kB"`},
+	{bytesize.Size(1024 * 1024), `"1.048576MB"`},
+	{bytesize.Size(1024 * 1024 * 1024), `"1.073741824GB"`},
+	{bytesize.Size(1024 * 1024 * 1024 * 1024), `"1.099511627776TB"`},
+	{bytesize.Size(math.MaxInt64), `"9223.372036854775807PB"`},
+	{bytesize.Size(1000), `"1kB"`},
+	{bytesize.Size(1000 * 1000), `"1MB"`},
+	{bytesize.Size(1000 * 1000 * 1000), `"1GB"`},
+	{bytesize.Size(1000 * 1000 * 1000 * 1000), `"1TB"`},
+	{bytesize.Size(1000 * 1000 * 1000 * 1000 * 1000), `"1PB"`},
+}
+
+func TestMarshalText(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range marshalTextTests {
+		data, err := json.Marshal(tc.in)
+		if err != nil {
+			t.Errorf("json.Marshal(%q) = _, err:%q", tc.in, err)
+		} else if string(data) != tc.expect {
+			t.Errorf("json.Marshal(%q) = %q, data does not equals %q", tc.in, data, tc.expect)
+		}
+	}
+}
+
+func TestUnmarshalText(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range marshalTextTests {
+		var data bytesize.Size
+		err := json.Unmarshal([]byte(tc.expect), &data)
+
+		if err != nil {
+			t.Errorf("json.Unmarshal(%q) = _, err:%q", tc.in, err)
+		} else if data != tc.in {
+			t.Errorf("json.Unmarshal(%q) = %q, data does not equals %q", tc.in, data, tc.expect)
+		}
+	}
+}