test_that("optimization works", {
    optimal_codons <- data.table::data.table(
        aa_code = rep('K', 2),
        codon = c('AAA', 'AAG'),
        coef = c(0.5, -0.5),
        subfam = c('Lys_AA', 'Lys_AA'))
    seq <- codon_optimize('AAGAAA', optimal_codons)
    expect_equal(as.character(seq), 'AAAAAA')
})