test_that("create_single_cell_complex_heatmap handles invalid inputs", {
  # Test with non-Seurat object
  expect_error(
    create_single_cell_complex_heatmap(mtcars, c("Gene1", "Gene2")),
    "seurat_object must be a Seurat object"
  )
  
  # Test with empty features
  expect_error(
    create_single_cell_complex_heatmap(mock_seurat, character(0)),
    "features must be a non-empty character vector"
  )
})

test_that("prepare_expression_matrices works correctly", {
  # Create mock Seurat object for testing
  skip_if_not_installed("Seurat")
  
  # Add actual tests with mock data
})

test_that("gene annotations are created correctly", {
  # Test gene grouping functionality
  # Add tests here
})