skip_on_cran()
skip_on_ci()
skip_if_not_installed("mvtnorm")

target <- runif(2, min = -50, max = 50)

p.log <- function(x) {
  dmvnorm(x, target, sigma = diag(2), log = TRUE)
}

unif_inits <- data.frame(
  a = runif(20),
  b = runif(20)
)

test_that("convergence stretch", {

  mcmcres <- MCMCEnsemble(
    p.log,
    inits=unif_inits,
    max.iter=1e5, n.walkers=20,
    method="stretch",
    coda=TRUE
  )

  expect_true(
    all(
      vapply(coda::HPDinterval(mcmcres$samples, 0.5), function(hpd) {
        all(
          target[1] > hpd[1, "lower"], target[1] < hpd[1, "upper"],
          target[2] > hpd[2, "lower"], target[2] < hpd[2, "upper"]
        )
      }, logical(1))
    )
  )

})

test_that("convergence differencial evolution", {

  mcmcres <- MCMCEnsemble(
    p.log,
    inits=unif_inits,
    max.iter=1e5, n.walkers=20,
    method="d",
    coda=TRUE
  )

  expect_true(
    all(
      vapply(coda::HPDinterval(mcmcres$samples, 0.5), function(hpd) {
        all(
          target[1] > hpd[1, "lower"], target[1] < hpd[1, "upper"],
          target[2] > hpd[2, "lower"], target[2] < hpd[2, "upper"]
        )
      }, logical(1))
    )
  )

})