tests/testthat/test-proporz.R

In polettif/proporz: Proportional Apportionment

test_that("generic proporz", {
    expect_identical(
        proporz(c(216, 310, 32), 20, "jefferson"),
        proporz(c(216, 310, 32), 20, "D'hondt"))
    expect_identical(
        proporz(c(216, 310, 32), 20, "Hagenbach-Bischoff"),
        proporz(c(216, 310, 32), 20, "hare-niemeyer"))
    expect_error(proporz(1,1, "unkown method"), "Unknown apportion method")
    v = c(10, 690, 210, 370)
    expect_identical(proporz(v*.02, 10, "round"), proporz(v*0.1, 10, "round"))
})

test_that("all method names", {
    for(m in names(proporz_methods)) {
        x = proporz(c(10, 20, 5), 3, m)
        expect_length(x, 3)
    }

    # ensure that package functions are used
    divisor_round = function(votes, n_seats, quorum) {
        stop("Used masking function in namespace!")
    }
    expect_identical(proporz(1:2, 1, "round"), c(0L, 1L))
})

test_that("undefined result errors", {
    expect_error(proporz(c(1, 10, 10), 1, "round"),
                 "Result is undefined, equal quotient for parties: 2, 3", fixed = TRUE)
    expect_error(proporz(c(1, X = 10, ABC = 10), 1, "round"),
                 "Result is undefined, equal quotient for parties: 'X', 'ABC'", fixed = TRUE)
    expect_identical(proporz(c(1, 10, 10), 2, "round"), c(0L,1L,1L))

    expect_error(largest_remainder_method(c(10, 10, 0), 1),
                 "Result is undefined, equal remainder for parties: 1, 2",
                 fixed = TRUE)
    expect_error(largest_remainder_method(c(A = 10, X = 10, P = 0), 1),
                 "Result is undefined, equal remainder for parties: 'A', 'X'",
                 fixed = TRUE)
})

test_that("huntington-hill", {
    # https://www.census.gov/data/tables/2020/dec/2020-apportionment-data.html
    us_census_2020 = structure(list(
        state = c("Alabama", "Alaska", "Arizona", "Arkansas", "California", "Colorado", "Connecticut", "Delaware", "Florida", "Georgia", "Hawaii", "Idaho", "Illinois", "Indiana", "Iowa", "Kansas", "Kentucky", "Louisiana", "Maine", "Maryland", "Massachusetts", "Michigan", "Minnesota", "Mississippi", "Missouri", "Montana", "Nebraska",
                  "Nevada", "New Hampshire", "New Jersey", "New Mexico", "New York", "North Carolina", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota", "Tennessee", "Texas", "Utah", "Vermont", "Virginia", "Washington", "West Virginia", "Wisconsin", "Wyoming"),
        population = c(5030053, 736081, 7158923, 3013756, 39576757, 5782171, 3608298, 990837, 21570527, 10725274, 1460137, 1841377, 12822739, 6790280, 3192406, 2940865, 4509342, 4661468, 1363582, 6185278, 7033469, 10084442, 5709752, 2963914, 6160281, 1085407,
                       1963333, 3108462, 1379089, 9294493, 2120220, 20215751, 10453948, 779702, 11808848, 3963516, 4241500, 13011844, 1098163, 5124712, 887770, 6916897, 29183290, 3275252, 643503, 8654542, 7715946, 1795045, 5897473, 577719),
        apportioned_representatives = c(7L, 1L, 9L, 4L, 52L, 8L, 5L, 1L, 28L, 14L, 2L, 2L, 17L, 9L, 4L, 4L, 6L, 6L, 2L, 8L, 9L, 13L, 8L, 4L, 8L, 2L, 3L, 4L, 2L, 12L, 3L, 26L, 14L, 1L, 15L, 5L, 6L, 17L, 2L, 7L, 1L, 9L, 38L, 4L, 1L, 11L, 10L, 2L, 8L, 1L)),
        row.names = c(NA, -50L), class = "data.frame")

    x = proporz(us_census_2020$population, 435, "huntington-hill")
    expect_identical(x, us_census_2020$apportioned_representatives)
})

test_that("sainte-lague", {
    stimmen1 = c(11828277, 9990488, 6316080, 5155933, 4643272, 2830238)
    expect_identical(divisor_round(stimmen1, 598),
                     as.integer(c(173, 146, 93, 76, 68, 42)))

    stimmen2 = c(430739, 143607, 242942, 1297940, 102419, 348216, 202850, 348082,
                 2678956, 328753, 812721, 216593, 520990, 1120018, 1051198, 144464)
    expect_identical(divisor_round(stimmen2, 146),
                     as.integer(c(6,2,4,19,2,5,3,5,39,5,12,3,8,16,15,2)))
})

test_that("huntington-hill and adams give at least one seat", {
    v = c(100, 1, 0, 10, 0)
    expect_identical(divisor_round(v, 3), c(3L,0L,0L,0L,0L))
    dc = divisor_ceiling(v, 3)
    expect_identical(dc, c(1L,1L,0L,1L,0L))
    expect_identical(proporz(v, 3, "huntington-hill"), dc)
    expect_identical(proporz(v, 3, "dean"), dc)
    expect_identical(proporz(v, 3, "adams"), dc)
})