context("Converting numeric vectors to natural parameters and back")

test_that("Wrong combinations trigger errors", {
  expect_error(parameters2natural(c(1, 3)), "provide a named parameter vector")
  expect_error(parameters2natural(c(mean = 1, var = 3)), "set does not match")
  expect_error(parameters2natural(c(mean = 1, sd = 3), "beta"), "parameter set")
  expect_error(natural2parameters(c(mean = 1, eta = 3)), "start with \"eta\"")
  expect_error(natural2parameters(c(1)), "must be a vector of two elements")
})

# Sampling values ==============================================================
x1 <- sample(1:100, 1)
x2 <- sample(1:100, 1)
p1 <- runif(1)
parm_beta <- c(shape1 = x1, shape2 = x2)
eta_beta <- c(eta1 = x1, eta2 = x2)
parm_bin <- c(size = x1, prob = p1)
eta_bin <- c(eta = log(p1 / (1 - p1)))
parm_ch <- c(df = x1)
eta_ch <- c(eta = x1 / 2 - 1)
parm_cbn <- c(lambda = p1)
eta_cbn <- c(eta = log(p1 / (1 - p1)))
parm_exp <- c(rate = x1)
eta_exp <- c(eta = -x1)
parm_gm1 <- c(shape = x1, rate = x2)
eta_gm1 <- c(eta1 = x1 - 1, eta2 = -x2)
parm_gm2 <- c(shape = x1, scale = x2)
eta_gm2 <- c(eta1 = x1 - 1, eta2 = -1 / x2)
parm_igm <- c(shape = x1, scale = x2)
eta_igm <- c(eta1 = -x1 - 1, eta2 = -x2)
parm_iga <- c(m = x1, s = x2)
eta_iga <- c(eta1 = - (1 / x2) / 2 / x1 ^ 2, eta2 = - (1 / x2) / 2)
parm_lnm <- c(meanlog = x1, sdlog = x2)
eta_lnm <- c(eta1 = x1 / x2 ^ 2, eta2 = - 1 / 2 / x2 ^ 2)
parm_nrm <- c(mean = x1, sd = x2)
eta_nrm <- c(eta1 = x1 / x2 ^ 2, eta2 = - 1 / 2 / x2 ^ 2)
parm_poi <- c(lambda = x1)
eta_poi <- c(eta = log(x1))

# Testing convertions ==========================================================
test_that("Converting to natural", {
  expect_equivalent(unclass(parameters2natural(parm_beta, "beta")), eta_beta)
  expect_equivalent(unclass(parameters2natural(parm_bin, "binomial")), eta_bin)
  expect_equivalent(unclass(parameters2natural(parm_ch, "chisq")), eta_ch)
  expect_equivalent(unclass(parameters2natural(parm_cbn, "contbern")), eta_cbn)
  expect_equivalent(unclass(parameters2natural(parm_exp, "exp")), eta_exp)
  expect_equivalent(unclass(parameters2natural(parm_gm1, "gamma")), eta_gm1)
  expect_equivalent(unclass(parameters2natural(parm_gm2, "gamma")), eta_gm2)
  expect_equivalent(unclass(parameters2natural(parm_igm, "invgamma")), eta_igm)
  expect_equivalent(unclass(parameters2natural(parm_iga, "invgauss")), eta_iga)
  expect_equivalent(unclass(parameters2natural(parm_lnm, "lognormal")), eta_lnm)
  expect_equivalent(unclass(parameters2natural(parm_nrm, "normal")), eta_nrm)
  expect_equivalent(unclass(parameters2natural(parm_poi, "poisson")), eta_poi)
})

test_that("Converting from natural", {
  expect_equivalent(unclass(natural2parameters(eta_beta, "beta")), parm_beta)
  expect_equivalent(unclass(natural2parameters(eta_bin, "binomial")), parm_bin[2])
  expect_equivalent(unclass(natural2parameters(eta_ch, "chisq")), parm_ch)
  expect_equivalent(unclass(natural2parameters(eta_cbn, "contbern")), parm_cbn)
  expect_equivalent(unclass(natural2parameters(eta_exp, "exp")), parm_exp)
  expect_equivalent(unclass(natural2parameters(eta_gm1, "gamma")), parm_gm1)
  expect_equivalent(unclass(natural2parameters(eta_igm, "invgamma")), parm_igm)
  expect_equivalent(unclass(natural2parameters(eta_iga, "invgauss")), parm_iga)
  expect_equivalent(unclass(natural2parameters(eta_lnm, "lognormal")), parm_lnm)
  expect_equivalent(unclass(natural2parameters(eta_nrm, "normal")), parm_nrm)
  expect_equivalent(unclass(natural2parameters(eta_poi, "poisson")), parm_poi)
})