tests/testthat/test-geese.R

In contrast: A Collection of Contrast Methods

context("geese models")

# ------------------------------------------------------------------------------

library(geepack)
library(nlme)

# from ?geese
data(seizure)
## Diggle, Liang, and Zeger (1994) pp166-168, compare Table 8.10
seiz.l <- reshape(
    seizure,
    varying = list(c("base", "y1", "y2", "y3", "y4")),
    v.names = "y",
    times = 0:4,
    direction = "long"
)
seiz.l <- seiz.l[order(seiz.l$id, seiz.l$time), ]
seiz.l$t <- ifelse(seiz.l$time == 0, 8, 2)
seiz.l$x <- ifelse(seiz.l$time == 0, 0, 1)
geese_fit_1 <- geese(
    y ~ offset(log(t)) + x + trt,
    id = id,
    data = seiz.l,
    corstr = "exch",
    family = poisson
)


test_that("geese models", {
    a_1 <- list(t = 8, trt = 0, x = 1)
    b_1 <- list(t = 8, trt = 1, x = 1)
    c_1 <- contrast(geese_fit_1, a_1, b_1)
    expect_equivalent(
        summary(geese_fit_1)$mean["trt", "p"],
        c_1$Pvalue
    )
})

test_that("printing", {
    a_1 <- list(t = 8, trt = 0, x = 1)
    b_1 <- list(t = 8, trt = 1, x = 1)
    c_1 <- contrast(geese_fit_1, a_1, b_1)
    expect_output(
        print(c_1),
        "geese model parameter contrast"
    )
})