test_that("slim rejects n=1", {
  x <- matrix(rnorm(4), nrow = 1, ncol = 4)
  y <- 1.0

  expect_error(
    slim(x, y, method = "lasso", verbose = FALSE),
    "At least two"
  )
})

test_that("slim rejects invalid method", {
  set.seed(201)
  x <- matrix(rnorm(60), nrow = 15, ncol = 4)
  y <- rnorm(15)

  expect_error(
    slim(x, y, method = "ridge", verbose = FALSE),
    "method"
  )
})

test_that("slim rejects q out of range", {
  set.seed(202)
  x <- matrix(rnorm(60), nrow = 15, ncol = 4)
  y <- rnorm(15)

  expect_error(
    slim(x, y, method = "lq", q = 0.5, verbose = FALSE),
    "q must be in"
  )
  expect_error(
    slim(x, y, method = "lq", q = 3, verbose = FALSE),
    "q must be in"
  )
})

test_that("slim rejects X/Y row mismatch", {
  set.seed(203)
  x <- matrix(rnorm(60), nrow = 15, ncol = 4)
  y <- rnorm(10)

  expect_error(
    slim(x, y, method = "lasso", verbose = FALSE),
    "same number of rows"
  )
})