stegage_test.go

package stegage_test

import (
	"bytes"
	"encoding/base64"
	"strings"
	"testing"

	"github.com/revelaction/stegage"
)

// From https://pkg.go.dev/image/png@go1.17.5#example-Decode
const gopherPng = `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`

// From https://pkg.go.dev/image#Image
const pikeCoxJpeg = `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`

const password = "73vb$#%51vf89vav9g&*%($C"
const data = "Lorem ipsum dolor sit amet"

func TestEncodeDecode(t *testing.T) {

	var images = []string{gopherPng, pikeCoxJpeg}

	for _, img := range images {

		imageR := base64.NewDecoder(base64.StdEncoding, strings.NewReader(img))

		passR := strings.NewReader(password)
		dataR := strings.NewReader(data)
		outEnc := new(bytes.Buffer)

		if err := stegage.Encode(passR, dataR, imageR, outEnc); err != nil {
			t.Fatal(err)
		}

		outDec := new(bytes.Buffer)

		passR = strings.NewReader(password)
		if err := stegage.Decode(passR, outEnc, outDec); err != nil {
			t.Fatal(err)
		}

		if string(outDec.Bytes()) != data {
			t.Errorf("wrong data: %q, expected %q", outDec.Bytes(), data)
		}

	}
}

func TestDecodeImageWithoutEncryptedFile(t *testing.T) {

	imageR := base64.NewDecoder(base64.StdEncoding, strings.NewReader(pikeCoxJpeg))

	out := new(bytes.Buffer)

	passR := strings.NewReader(password)
	if err := stegage.Decode(passR, imageR, out); err == nil {

		t.Fatal("Uncaught error: Image without encrypted age payload")
	}
}

func TestDecodeWrongPassword(t *testing.T) {

	imageR := base64.NewDecoder(base64.StdEncoding, strings.NewReader(pikeCoxJpeg))

	passR := strings.NewReader(password)
	dataR := strings.NewReader(data)
	outEnc := new(bytes.Buffer)

	if err := stegage.Encode(passR, dataR, imageR, outEnc); err != nil {
		t.Fatal(err)
	}

	outDec := new(bytes.Buffer)

	wrongPassR := strings.NewReader("wrong password")
	if err := stegage.Decode(wrongPassR, outEnc, outDec); err == nil {
		t.Fatal("Uncaught error: Wrong password")
	}
}

func TestEncodeEmptyPassword(t *testing.T) {

	imageR := base64.NewDecoder(base64.StdEncoding, strings.NewReader(gopherPng))

	passR := strings.NewReader("")
	dataR := strings.NewReader(data)
	outEnc := new(bytes.Buffer)

	if err := stegage.Encode(passR, dataR, imageR, outEnc); err == nil {
		t.Fatal("Uncaught error: Empty password")
	}
}

func TestDecodeEmptyPassword(t *testing.T) {

	imageR := base64.NewDecoder(base64.StdEncoding, strings.NewReader(pikeCoxJpeg))

	passR := strings.NewReader(password)
	dataR := strings.NewReader(data)
	outEnc := new(bytes.Buffer)

	if err := stegage.Encode(passR, dataR, imageR, outEnc); err != nil {
		t.Fatal(err)
	}

	outDec := new(bytes.Buffer)

	emptyPassR := strings.NewReader("")
	if err := stegage.Decode(emptyPassR, outEnc, outDec); err == nil {
		t.Fatal("Uncaught error: Empty password")
	}
}

func TestEncodeNotSupportedImageFormat(t *testing.T) {

	notImageR := strings.NewReader("Not a supported image content")
	passR := strings.NewReader(password)
	dataR := strings.NewReader(data)
	out := new(bytes.Buffer)

	if err := stegage.Encode(passR, dataR, notImageR, out); err == nil {
		t.Fatal("Uncaught error: Not supported Image")
	}
}

func TestDecodeNotSupportedImageFormat(t *testing.T) {

	notImageR := strings.NewReader("Not a supported image content")
	passR := strings.NewReader(password)
	out := new(bytes.Buffer)

	if err := stegage.Decode(passR, notImageR, out); err == nil {
		t.Fatal("Uncaught error: Not supported Image")
	}
}