test_that("create_single_cell_complex_heatmap handles invalid inputs", {
  skip("Requires mock Seurat object")
  # mock_seurat <- ... # define a minimal Seurat object if you want to test
  # 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
})