func assertAnonymisationFunction(t *testing.T, expected Anonymisation, actual Anonymisation, value string) {
	require.NotNil(t, expected)
	require.NotNil(t, actual)
	expectedRes, expectedErr := expected(value)
	actualRes, actualErr := actual(value)
	assert.Equal(t, expectedRes, actualRes)
	assert.Equal(t, expectedErr, actualErr)
}
can't test that the functions are equal because of https://github.com/stretchr/testify/issues/182
and https://github.com/stretchr/testify/issues/159#issuecomment-99557398
will have to test that the functions return the same
package main
import (
	"math/rand"
	"testing"
	"github.com/leanovate/gopter"
	"github.com/leanovate/gopter/gen"
	"github.com/leanovate/gopter/prop"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)
var salt = "jump"
const seed = int64(1)
const firstSalt = "5577006791947779410"