tests/testthat/test-zeroinfl.R

In ggeffects: Create Tidy Data Frames of Marginal Effects for 'ggplot' from Model Outputs

if (suppressWarnings(
  requiet("testthat") &&
  requiet("ggeffects") &&
  requiet("glmmTMB") &&
  requiet("pscl")
)) {
  data(Salamanders)

  m1 <- zeroinfl(count ~ mined | mined, dist = "poisson", data = Salamanders)
  m2 <- hurdle(count ~ mined | mined, dist = "poisson", zero.dist = "poisson", data = Salamanders)
  m3 <- hurdle(count ~ mined | mined, dist = "poisson", zero.dist = "binomial", data = Salamanders)
  m4 <- hurdle(count ~ mined | mined, dist = "poisson", zero.dist = "binomial", link = "log", data = Salamanders)
  m5 <- suppressWarnings(zeroinfl(count ~ mined | mined, dist = "negbin", link = "log", data = Salamanders))

  test_that("ggpredict, pscl", {
    expect_s3_class(ggpredict(m1, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggpredict(m1, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggpredict(m2, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggpredict(m2, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggpredict(m3, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggpredict(m3, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggpredict(m4, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggpredict(m4, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggpredict(m5, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggpredict(m5, "mined", type = "fe.zi"), "data.frame")
  })

  test_that("ggpredict, pscl", {
    skip_on_cran()
    set.seed(123)
    pr <- ggpredict(m1, "mined", type = "fe.zi")
    expect_equal(pr$conf.low, c(0.1731, 2.0172), tolerance = 1e-3)

    model <- zeroinfl(count ~ mined * spp | mined * spp, dist = "poisson", data = Salamanders)
    set.seed(123)
    pr <- ggpredict(model, c("mined", "spp"), type = "fe.zi")
    expect_equal(
      pr$conf.low,
      c(0, 0, 0.03704, 1e-05, 1e-05, 0.14815, 0.13418, 1.61886,
        0.04808, 1.81329, 0.48571, 3.07055, 3.1093, 1.33136),
      tolerance = 1e-2
    )
  })

  test_that("ggemmeans, pscl", {
    expect_s3_class(ggemmeans(m1, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggemmeans(m1, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggemmeans(m2, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggemmeans(m2, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggemmeans(m3, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggemmeans(m3, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggemmeans(m4, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggemmeans(m4, "mined", type = "fe.zi"), "data.frame")
    expect_s3_class(ggemmeans(m5, "mined", type = "fe"), "data.frame")
    expect_s3_class(ggemmeans(m5, "mined", type = "fe.zi"), "data.frame")
  })

  test_that("compare, pscl", {
    p1 <- ggemmeans(m1, "mined", type = "fe")
    p2 <- ggpredict(m1, "mined", type = "fe")
    expect_equal(p1$predicted[1], p2$predicted[1], tolerance = 1e-3)

    p1 <- ggemmeans(m1, "mined", type = "fe.zi")
    p2 <- ggpredict(m1, "mined", type = "fe.zi")
    expect_equal(p1$predicted[1], p2$predicted[1], tolerance = 1e-3)

    p1 <- ggemmeans(m2, "mined", type = "fe")
    p2 <- ggpredict(m2, "mined", type = "fe")
    expect_equal(p1$predicted[1], p2$predicted[1], tolerance = 1e-3)

    p1 <- ggemmeans(m2, "mined", type = "fe.zi")
    p2 <- ggpredict(m2, "mined", type = "fe.zi")
    expect_equal(p1$predicted[1], p2$predicted[1], tolerance = 1e-3)

    p1 <- ggemmeans(m5, "mined", type = "fe")
    p2 <- ggpredict(m5, "mined", type = "fe")
    expect_equal(p1$predicted[1], p2$predicted[1], tolerance = 1e-3)

    p1 <- ggemmeans(m5, "mined", type = "fe.zi")
    p2 <- ggpredict(m5, "mined", type = "fe.zi")
    expect_equal(p1$predicted[1], p2$predicted[1], tolerance = 1e-3)
  })

  #Generate some data

  set.seed(123)
  N <- 100 #Samples
  x <- runif(N, 0, 5) #Predictor 1
  z <- runif(N, 0, 5) #Predictor 2
  off <- rgamma(N, 3, 2) #Offset variable
  yhat <- -1 + x * 0.2 + z * -0.2 + z * x * 0.2 + log(off) #Prediction on log scale
  dat <- data.frame(y = NA, x,z, logOff = log(off)) #Storage dataframe

  dat$y <- rpois(N, exp(yhat)) #Poisson process
  dat$y <- ifelse(rbinom(N, 1, 0.3), 0, dat$y) #Zero-inflation process

  #Fit zeroinfl and glm model

  #Interaction b/w x and z
  model <- zeroinfl(y ~ offset(logOff) + x * z | 1, data = dat, dist = 'poisson')

  test_that("pscl, offset, interaction and CI", {
    pr <- ggpredict(model, c("x", "z"))
    expect_equal(
      pr$conf.low,
      c(0.10175, 0.10842, 0.07738, 0.15311, 0.17543, 0.14137, 0.2299,
        0.28352, 0.25811, 0.34404, 0.45742, 0.47084, 0.51189, 0.73575,
        0.85762, 0.75364, 1.17695, 1.55786, 1.08708, 1.86238, 2.81383,
        1.51007, 2.8848, 5.01418, 1.9918, 4.32397, 8.65455, 2.51388,
        6.28353, 14.25571, 3.09229, 8.96366, 22.76232),
      tolerance = 1e-3
    )
  })

}