# Tests for get_robust_cov()
# Run with: devtools::test() or testthat::test_file("tests/testthat/test-robust_cov.R")

test_that("get_robust_cov returns a list with center and cov", {
  set.seed(1)
  X <- matrix(rnorm(60 * 3), nrow = 60, ncol = 3)
  result <- get_robust_cov(X, method = "mcd")

  expect_type(result, "list")
  expect_named(result, c("center", "cov"))
})

test_that("center has correct length", {
  set.seed(1)
  X <- matrix(rnorm(60 * 4), nrow = 60, ncol = 4)
  result <- get_robust_cov(X, method = "mcd")

  expect_length(result$center, 4)
})

test_that("covariance matrix has correct dimensions", {
  set.seed(1)
  X <- matrix(rnorm(60 * 4), nrow = 60, ncol = 4)
  result <- get_robust_cov(X, method = "mcd")

  expect_equal(dim(result$cov), c(4, 4))
})

test_that("covariance matrix is symmetric", {
  set.seed(1)
  X <- matrix(rnorm(60 * 3), nrow = 60, ncol = 3)
  result <- get_robust_cov(X, method = "mcd")

  expect_equal(result$cov, t(result$cov), tolerance = 1e-10)
})

test_that("all seven estimators run without error", {
  set.seed(1)
  X <- matrix(rnorm(80 * 3), nrow = 80, ncol = 3)
  methods <- c("mcd", "mve", "mest", "mmest", "sde", "sest", "ogk")

  for (m in methods) {
    expect_no_error(get_robust_cov(X, method = m))
  }
})

test_that("method is case-insensitive", {
  set.seed(1)
  X <- matrix(rnorm(60 * 3), nrow = 60, ncol = 3)

  expect_no_error(get_robust_cov(X, method = "MCD"))
  expect_no_error(get_robust_cov(X, method = "Mcd"))
})

test_that("invalid method raises an error", {
  set.seed(1)
  X <- matrix(rnorm(60 * 3), nrow = 60, ncol = 3)

  expect_error(get_robust_cov(X, method = "unknown"),
               regexp = "must be one of")
})

test_that("non-numeric data raises an error", {
  X <- data.frame(a = letters[1:10], b = 1:10)
  expect_error(get_robust_cov(X))
})

test_that("single-row data raises an error", {
  X <- matrix(1:5, nrow = 1)
  expect_error(get_robust_cov(X), regexp = "at least 2 rows")
})

test_that("data frame input is accepted", {
  set.seed(1)
  X <- as.data.frame(matrix(rnorm(60 * 3), nrow = 60, ncol = 3))
  expect_no_error(get_robust_cov(X, method = "mcd"))
})