test_that("functions handle NULL input gracefully", {
  skip_on_cran()
  
  # Test spanner_pal with no arguments
  expect_silent(spanner_pal())
  
  # Test cylinderFit with NULL data
  expect_error(cylinderFit(NULL, method = "ransac"))
  
  # Test las2xyz with NULL
  expect_error(las2xyz(NULL))
})

test_that("functions handle empty data", {
  skip_if_not_installed("lidR")
  skip_on_cran()
  
  # Create empty data frame
  empty_df <- data.frame(X = numeric(0), Y = numeric(0), Z = numeric(0))
  
  # Test cylinderFit with empty data
  expect_error(cylinderFit(empty_df, method = "ransac"))
})

test_that("functions validate parameter ranges", {
  skip_if_not_installed("lidR")
  skip_if_not_installed("terra")
  skip_on_cran()
  
  # Create minimal test data
  test_raster <- terra::rast(ncol = 5, nrow = 5)
  terra::values(test_raster) <- 1:25
  
  # Test with empty suitability list
  expect_error(process_rasters_patchmorph(test_raster, c(), c(1), c(1)))
  
  # Test with empty gap list
  expect_error(process_rasters_patchmorph(test_raster, c(1), c(), c(1)))
  
  # Test with empty spur list
  expect_error(process_rasters_patchmorph(test_raster, c(1), c(1), c()))
})

test_that("numeric outputs are valid", {
  skip_if_not_installed("lidR")
  skip_on_cran()
  
  # Test that spanner_pal returns valid colors
  pal <- spanner_pal()
  
  # All should be valid hex colors
  expect_true(all(grepl("^#[0-9A-Fa-f]{6}$", pal)))
  
  # Test that cylinder fitting returns positive radius
  xyz <- create_test_cylinder(radius = 0.2, height = 2, n_points = 100)
  las_obj <- lidR::LAS(xyz)
  result <- cylinderFit(las_obj, method = "ransac", n_best = 5, n = 10,
                        inliers = 0.8, conf = 0.95)
  
  expect_true(result$radius > 0)
  expect_true(all(is.finite(c(result$px, result$py, result$pz))))
})

test_that("functions maintain data integrity", {
  skip_if_not_installed("lidR")
  skip_on_cran()
  
  # Create test LAS
  las_data <- data.frame(
    X = runif(50, 0, 10),
    Y = runif(50, 0, 10),
    Z = runif(50, 0, 5)
  )
  las <- lidR::LAS(las_data)
  
  # Convert to xyz
  xyz <- las2xyz(las)
  
  # Check that coordinate values are preserved
  expect_equal(xyz$X, las_data$X)
  expect_equal(xyz$Y, las_data$Y)
  expect_equal(xyz$Z, las_data$Z)
})

test_that("functions handle extreme values", {
  skip_if_not_installed("terra")
  skip_on_cran()
  
  # Create raster with extreme values
  test_raster <- terra::rast(ncol = 5, nrow = 5)
  terra::values(test_raster) <- c(rep(0, 20), rep(1e6, 5))
  
  # Should not error with large values
  result <- process_rasters_patchmorph(test_raster, c(100), c(1), c(1))
  expect_type(result, "list")
  expect_true(length(result) > 0)
})