# uses su_eg2 & su_m_bivar_te
## load packages
library("testthat")

# partial derivatives
test_that("partial derivatives works with single data point", {
    # data slice through te(x,z) holding z == 0.4
    ds <- data_slice(su_m_bivar_te, x = 0.0204313075, z = 0.4)
    expect_silent(pd_x <- partial_derivatives(su_m_bivar_te, data = ds,
        type = "central", focal = "x"))
})