transform_test.go

package cryptanalysis

import (
	"bytes"
	"testing"
)

func TestChunk(t *testing.T) {
	data := []byte("TESTDATA")

	res3 := [][]byte{}
	res3 = append(res3, []byte("TES"))
	res3 = append(res3, []byte("TDA"))
	res3 = append(res3, []byte("TA\x01"))

	res4 := [][]byte{}
	res4 = append(res4, []byte("TEST"))
	res4 = append(res4, []byte("DATA"))
	res4 = append(res4, []byte("\x04\x04\x04\x04"))

	c3 := Chunk(PadPkcs7(data, 9), 3)
	c4 := Chunk(PadPkcs7(data, 12), 4)

	for i, _ := range res3 {
		if bytes.Compare(res3[i], c3[i]) != 0 {
			t.Error("Expected", res3, "got", c3)
		}
	}

	for i, _ := range res4 {
		if bytes.Compare(res4[i], c4[i]) != 0 {
			t.Error("Expected", res4, "got", c4)
		}
	}
}

func TestTranspose(t *testing.T) {
	m1 := [][]byte{}
	m1 = append(m1, []byte{1, 2})
	m1 = append(m1, []byte{3, 4})

	m2 := [][]byte{}
	m2 = append(m2, []byte{1, 3})
	m2 = append(m2, []byte{2, 4})

	m3 := Transpose(m1)

	for i, _ := range m2 {
		if bytes.Compare(m2[i], m3[i]) != 0 {
			t.Error("Expected", m2, "got", m3)
		}
	}
}

func TestPadPkcs7(t *testing.T) {
	str := []byte("YELLOW SUBMARINE")
	pad := []byte("YELLOW SUBMARINE\x04\x04\x04\x04")
	pkcs := PadPkcs7(str, 20)

	if bytes.Compare(pkcs, pad) != 0 {
		t.Error("Expected", pad, "got", pkcs)
	}
}

func TestCaesarShift(t *testing.T) {
	str := "YellowSubmarine"
	shifted := "LryybjFhoznevar"
	test := CaesarShift(str, 13)

	if test != shifted {
		t.Error("Expected", shifted, "got", test)
	}

	test = CaesarShift(shifted, 13)

	if test != str {
		t.Error("Expected", str, "got", test)
	}
}