dissertation-2-code/proxy/packet_test.go

package proxy

import (
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"mpbl3p/mocks"
	"mpbl3p/shared"
	"testing"
)

func TestAppendMac(t *testing.T) {
	testContent := []byte("A test string is the content of this packet.")
	testMac := mocks.AlmostUselessMac("abcd")
	testPacket := SimplePacket(testContent)
	testMarshalled := testPacket.Marshal()

	appended := AppendMac(testMarshalled, testMac)

	t.Run("Length", func(t *testing.T) {
		assert.Len(t, appended, len(testMarshalled)+4)
	})

	t.Run("Mac", func(t *testing.T) {
		assert.Equal(t, []byte{'a', 'b', 'c', 'd'}, appended[len(testMarshalled):])
	})

	t.Run("Original", func(t *testing.T) {
		assert.Equal(t, testMarshalled, appended[:len(testMarshalled)])
	})
}

func TestStripMac(t *testing.T) {
	testContent := []byte("A test string is the content of this packet.")
	testMac := mocks.AlmostUselessMac("abcd")
	testPacket := SimplePacket(testContent)
	testMarshalled := testPacket.Marshal()

	appended := AppendMac(testMarshalled, testMac)

	t.Run("Length", func(t *testing.T) {
		cut, err := StripMac(appended, testMac)

		require.Nil(t, err)
		assert.Len(t, cut, len(testMarshalled))
	})

	t.Run("IncorrectMac", func(t *testing.T) {
		badMac := make([]byte, len(testMarshalled)+4)
		copy(badMac, testMarshalled)
		copy(badMac[:len(testMarshalled)], "dcba")
		_, err := StripMac(badMac, testMac)

		assert.Error(t, err, shared.ErrBadChecksum)
	})

	t.Run("Original", func(t *testing.T) {
		cut, err := StripMac(appended, testMac)

		require.Nil(t, err)
		assert.Equal(t, testMarshalled, cut)
	})
}