## ---- test-direct-std
lapply(
  X = 1,
  FUN = function(i,
                 text,
                 tol) {
    message(text)
    answer <- -0.30032315
    phi <- matrix(
      data = c(
        -0.357, 0.771, -0.450,
        0.0, -0.511, 0.729,
        0, 0, -0.693
      ),
      nrow = 3
    )
    colnames(phi) <- rownames(phi) <- c("x", "m", "y")
    sigma <- matrix(
      data = c(
        0.24455556, 0.02201587, -0.05004762,
        0.02201587, 0.07067800, 0.01539456,
        -0.05004762, 0.01539456, 0.07553061
      ),
      nrow = 3
    )
    delta_t <- 2
    testthat::test_that(
      paste(text, "DirectStd"),
      {
        testthat::expect_true(
          (
            answer - DirectStd(
              phi = phi,
              sigma = sigma,
              delta_t = delta_t,
              from = "x",
              to = "y",
              med = "m"
            )$output
          ) <= tol
        )
      }
    )
    testthat::test_that(
      paste(text, "MedStd"),
      {
        testthat::expect_true(
          (
            answer - MedStd(
              phi = phi,
              sigma = sigma,
              delta_t = delta_t,
              from = "x",
              to = "y",
              med = "m"
            )$output[, "direct"]
          ) <= tol
        )
      }
    )
    med <- MedStd(
      phi = phi,
      sigma = sigma,
      delta_t = 1:5,
      from = "x",
      to = "y",
      med = "m"
    )
    print(med)
    summary(med)
    plot(med)
    plot(med, col = 1:3)
    med <- MedStd(
      phi = phi,
      sigma = sigma,
      delta_t = 1,
      from = "x",
      to = "y",
      med = "m"
    )
    print(med)
    summary(med)
    testthat::test_that(
      paste(text, "plot error"),
      {
        testthat::expect_error(
          plot(med)
        )
      }
    )
    direct <- DirectStd(
      phi = phi,
      sigma = sigma,
      delta_t = delta_t,
      from = "x",
      to = "y",
      med = "m"
    )
    print(direct)
  },
  text = "test-direct-std",
  tol = 0.01
)