`check_areas("00")` threw an error with unexpected message.
Expected match: "areas codes must take the form XX or XX-YY, the following are invalid: 00"
Actual message: "Area codes must take the form XX, XX-YY, or XX-YYY. The following are invalid: 00"

test_that("correctly checks indicator names", {
regexp="indicators must be 6-letter codes, the following are invalid: 999", fixed=TRUE)
regexp="indicators must be 6-letter codes, the following are invalid: 998, 999", fixed=TRUE)
regexp="indicators must be 6-letter codes, the following are invalid: all", fixed=TRUE)
test_that("correctly checks area codes", {
regexp="areas codes must take the form XX or XX-YY, the following are invalid: 00", fixed=TRUE)
regexp="areas codes must take the form XX or XX-YY, the following are invalid: 00, 01", fixed=TRUE)
regexp="areas codes must take the form XX or XX-YY, the following are invalid: all", fixed=TRUE)
expect_error(check_years(10), regexp="the following years are invalid: 10", fixed=TRUE)
expect_error(check_years(c(10, 11)), regexp="the following years are invalid: 10, 11", fixed=TRUE)
expect_error(check_years(c(10, "2000", 11)), regexp="the following years are invalid: 10, 11", fixed=TRUE)
expect_error(check_years(c(2000, "all")), regexp="the following years are invalid: all", fixed=TRUE)
regexp="percentiles must take the form pXX or pXXpYY, the following are invalid: pAAp100", fixed=TRUE)
regexp="percentiles must take the form pXX or pXXpYY, the following are invalid: pAA, pBBp100", fixed=TRUE)
regexp="percentiles must take the form pXX or pXXpYY, the following are invalid: pAA, p1pBB", fixed=TRUE)
regexp="percentiles must take the form pXX or pXXpYY, the following are invalid: all", fixed=TRUE)
test_that("correctly checks age codes", {
regexp="ages must be numerical codes between 100 and 999, the following are invalid: 10", fixed=TRUE)
regexp="ages must be numerical codes between 100 and 999, the following are invalid: 10, 11", fixed=TRUE)
regexp="ages must be numerical codes between 100 and 999, the following are invalid: all", fixed=TRUE)
test_that("correctly checks population codes", {
regexp="population codes must be 'i', 'j', 'm', 'f', 't' or 'e', the following are invalid: 10", fixed=TRUE)
regexp="population codes must be 'i', 'j', 'm', 'f', 't' or 'e', the following are invalid: 10, ij", fixed=TRUE)
regexp="population codes must be 'i', 'j', 'm', 'f', 't' or 'e', the following are invalid: all", fixed=TRUE)