Absence of NA values assertion
Passes if the actual value, Vector, List, or DataFrame (optional column) contains zero NA values.
actual (Any): The value, container,
or DataFrame to check.
col (String): (Optional) Column
name when checking a DataFrame.
Expect_pass when no NA values exist;
Expect_stop if NA values are found.
assert(expect_no_na([1, 2, 3]))
assert(expect_no_na(df, "val"))