test_that("vparse handles different input formats correctly", { expect_equal(vparse(Treatment, Type), c("Treatment", "Type")) expect_equal(vparse(c("Treatment", "Type")), c("Treatment", "Type")) expect_equal(vparse(~Treatment + Type), c("Treatment", "Type")) }) test_that("vselect selects correct columns from CO2", { data(CO2) selected <- vselect(CO2, Treatment, Type) expect_true(all(c("Treatment", "Type") %in% names(selected))) expect_equal(ncol(selected), 2) }) test_that("vcheck confirms variables exist", { data(CO2) expect_true(vcheck(CO2, Treatment, Type)) expect_true(vcheck(CO2, ~Treatment + Type)) }) test_that("vcheck throws error for missing variables", { data(CO2) expect_error(vcheck(CO2, Nonexistent), "Missing variables") }) test_that("vmap applies function to variable names", { result <- vmap(~Treatment + Type, toupper) expect_equal(result, list("TREATMENT", "TYPE")) }) test_that("vrename renames columns correctly", { data(CO2) renamed <- vrename(CO2, c(Treatment = "Trt", Type = "Group")) expect_true(all(c("Trt", "Group") %in% names(renamed))) expect_false("Treatment" %in% names(renamed)) })