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test_that("string_boundary_linter skips allowed grepl() usages", {
linter <- string_boundary_linter()
# no known start/end anchor --> no lint
expect_lint("grepl(p1, x)", NULL, linter)
# no start/end anchor --> no lint
expect_lint("grepl('abc', x)", NULL, linter)
# regex pattern --> no lint
expect_lint("grepl('^[a-z]', x)", NULL, linter)
expect_lint("grepl('[a-z]$', x)", NULL, linter)
# ignore.case --> no lint
expect_lint("grepl('^abc', x, ignore.case = TRUE)", NULL, linter)
expect_lint("grepl('^abc', x, ignore.case = ignore.case)", NULL, linter)
# fixed --> no lint
expect_lint("grepl('^abc', x, fixed = TRUE)", NULL, linter)
expect_lint("grepl('^abc', x, fixed = fixed)", NULL, linter)
})
test_that("string_boundary_linter skips allowed str_detect() usages", {
linter <- string_boundary_linter()
# no known start/end anchor --> no lint
expect_lint("str_detect(x, p1)", NULL, linter)
# no start/end anchor --> no lint
expect_lint("str_detect(x, 'abc')", NULL, linter)
# regex pattern --> no lint
expect_lint("str_detect(x, '^[a-z]')", NULL, linter)
expect_lint("str_detect(x, '[a-z]$')", NULL, linter)
})
test_that("string_boundary_linter skips allowed substr()/substring() usages", {
linter <- string_boundary_linter()
# no comparison operator --> no lint
expect_lint("substr(x, start, end)", NULL, linter)
# unknown indices --> no lint
expect_lint("substr(x, start, end) == 'a'", NULL, linter)
expect_lint("substring(x, start, end) == 'a'", NULL, linter)
# using foo(nchar(.))
expect_lint("substring(x, nchar(x) - 4, nchar(x) - 1) == 'abc'", NULL, linter)
# using nchar(), but not of the input
expect_lint("substring(x, nchar(y) - 4, nchar(y)) == 'abcd'", NULL, linter)
# using x in nchar(), but on foo(input)
expect_lint("substring(x, nchar(foo(x)) - 4, nchar(foo(x))) == 'abcd'", NULL, linter)
# _close_ to equivalent, but not so in general -- e.g.
# substring(s <- "abcdefg", 2L) == "efg" is not TRUE, but endsWith(s, "efg")
# is. And if `s` contains strings of varying lengths, there's no equivalent.
expect_lint("substring(x, 2L)", NULL, linter)
})
test_that("string_boundary_linter blocks simple disallowed grepl() usages", {
linter <- string_boundary_linter()
starts_message <- rex::rex("Use !is.na(x) & startsWith(x, string) to detect a fixed initial substring,")
ends_message <- rex::rex("Use !is.na(x) & endsWith(x, string) to detect a fixed terminal substring,")
expect_lint("grepl('^a', x)", starts_message, linter)
# non-trivially equivalent (but still same as startsWith())
expect_lint("grepl('^[.]', x)", starts_message, linter)
expect_lint("grepl('a$', x)", ends_message, linter)
# also get negation for free
expect_lint("!grepl('a$', x)", ends_message, linter)
# perl = TRUE doesn't matter
expect_lint("grepl('^a', x, perl = TRUE)", starts_message, linter)
# explicit FALSE (i.e., an explicit default) is ignored
expect_lint("grepl('^a', x, fixed = FALSE)", starts_message, linter)
expect_lint("grepl('^a', x, fixed = F)", starts_message, linter)
})
test_that("string_boundary_linter blocks simple disallowed str_detect() usages", {
linter <- string_boundary_linter()
expect_lint(
"str_detect(x, '^a')",
rex::rex("Use startsWith() to detect a fixed initial substring."),
linter
)
expect_lint(
"str_detect(x, 'a$')",
rex::rex("Use endsWith() to detect a fixed terminal substring."),
linter
)
})
test_that("string_boundary_linter blocks disallowed substr()/substring() usage", {
linter <- string_boundary_linter()
starts_message <- rex::rex("Use startsWith() to detect an initial substring.")
ends_message <- rex::rex("Use endsWith() to detect a terminal substring.")
expect_lint("substr(x, 1L, 2L) == 'ab'", starts_message, linter)
# end doesn't matter, just anchoring to 1L
expect_lint("substr(x, 1L, end) == 'ab'", starts_message, linter)
expect_lint("substring(x, nchar(x) - 4L, nchar(x)) == 'abcde'", ends_message, linter)
# start doesn't matter, just anchoring to nchar(x)
expect_lint("substring(x, start, nchar(x)) == 'abcde'", ends_message, linter)
# more complicated expressions
expect_lint("substring(colnames(x), start, nchar(colnames(x))) == 'abc'", ends_message, linter)
})
test_that("plain ^ or $ are skipped", {
linter <- string_boundary_linter()
expect_lint('grepl("^", x)', NULL, linter)
expect_lint('grepl("$", x)', NULL, linter)
})
test_that("substr inverted tests are caught as well", {
linter <- string_boundary_linter()
expect_lint(
"substr(x, 1L, 2L) != 'ab'",
rex::rex("Use startsWith() to detect an initial substring."),
linter
)
expect_lint(
"substring(x, nchar(x) - 4L, nchar(x)) != 'abcde'",
rex::rex("Use endsWith() to detect a terminal substring."),
linter
)
})
test_that("R>=4 raw strings are detected", {
linter <- string_boundary_linter()
skip_if_not_r_version("4.0.0")
expect_lint('grepl(R"(^.{3})", x)', NULL, linter)
expect_lint(
'grepl(R"(^abc)", x)',
rex::rex("Use !is.na(x) & startsWith(x, string) to detect a fixed initial substring,"),
linter
)
})
test_that("grepl() can optionally be ignored", {
linter <- string_boundary_linter(allow_grepl = TRUE)
expect_lint("grepl('^abc', x)", NULL, linter)
expect_lint("grepl('xyz$', x)", NULL, linter)
})
test_that("whole-string regex recommends ==, not {starts,ends}With()", {
linter <- string_boundary_linter()
lint_msg <- rex::rex("Use == to check for an exact string match.")
expect_lint("grepl('^abc$', x)", lint_msg, linter)
expect_lint("grepl('^a\\\\.b$', x)", lint_msg, linter)
expect_lint("str_detect(x, '^abc$')", lint_msg, linter)
expect_lint("str_detect(x, '^a[.]b$')", lint_msg, linter)
})
test_that("vectorization + metadata work as intended", {
expect_lint(
trim_some("{
substring(a, 1, 3) == 'abc'
substring(b, nchar(b) - 3, nchar(b)) == 'defg'
substr(c, 1, 3) == 'hij'
substr(d, nchar(d) - 3, nchar(d)) == 'klmn'
grepl('^abc', e)
grepl('abc$', f)
grepl('^abc$', g)
str_detect(h, '^abc')
str_detect(i, 'abc$')
str_detect(j, '^abc$')
}"),
list(
list("startsWith", line_number = 2L),
list("endsWith", line_number = 3L),
list("startsWith", line_number = 4L),
list("endsWith", line_number = 5L),
list("startsWith", line_number = 6L),
list("endsWith", line_number = 7L),
list("==", line_number = 8L),
list("startsWith", line_number = 9L),
list("endsWith", line_number = 10L),
list("==", line_number = 11L)
),
string_boundary_linter()
)
})
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