# Check that gev_influence() behaves as expected

# Influence curve for the default mu = 0, sigma = 1, xi = 0 case
z <- seq(from = -3, to = 3, by = 1)
inf1 <- gev_influence(z = z)

# Influence curve for the default mu = 0, sigma = 1, xi = 0 case
z <- seq(from = -3, to = 3, by = 1)
inf2 <- gev_influence(z = z, mu = 2)

# Influence curve for the default mu = 0, sigma = 1, xi = 0 case
z <- seq(from = -3, to = 3, by = 1)
inf3 <- gev_influence(z = z, mu = 2, sigma = 2)

test_that("GEV influence for mu and sigma scale with sigma", {
  testthat::expect_equal(inf2[, 3:4] * 2, inf3[, 3:4])
})

# Check that the GEV influence function for mu is identical to that for
# the 1 / (1 - exp(-1)) return level
z <- seq(from = -3, to = 3, by = 1)
m <- c(1 / (1 - exp(-1)), 50, 100)
infmu <- gev_influence(z = z, mu = 0, sigma = 1, xi = 0.1)
infrl <- gev_influence_rl(z = z, mu = 0, sigma = 1, xi = 0.1, m = m)

test_that("GEV influence fn for mu = that for corresponding return level", {
  testthat::expect_equal(infmu[, 3], infrl[, 3])
})

# Check that we can pass graphical parameters to plot.gev_influence() and
# plot.gev_influence_rl() pass

par_input <- list(x = infmu, main = "", cex.axis = 1.25, cex.lab = 1.5,
                  col = 3:1, lty = 3:1, lwd = 1:3)
par_output <- do.call(plot, par_input)
test_that("plot.gev_influence() graphical parameters", {
  testthat::expect_equal(par_output, par_input[-1])
})

par_input <- list(x = infrl, main = "", cex.axis = 1.25, cex.lab = 1.5,
                  col = 3:1, lty = 3:1, lwd = 1:3)
par_output <- do.call(plot, par_input)
test_that("plot.gev_influence_rl() graphical parameters", {
  testthat::expect_equal(par_output, par_input[-1])
})