add requires_utf8 argument to tests

NEWS.md

@@ -40,6 +40,8 @@
 
 4. Removed use of non-API `ATTRIB`, `SET_ATTRIB`, and `findVar` [#6180](https://github.com/Rdatatable/data.table/issues/6180). Thanks @aitap for the continued assiduous work here, and @MichaelChirico for the easy fix to replace `findVar` with `R_getVar`.
 
+5. The data.table test suite is a bit more robust to lacking UTF-8 support via a new `requires_utf8` argument to `test()` to skip tests when UTF-8 support is not available, [#7336](https://github.com/Rdatatable/data.table/issues/7336). Thanks @MichaelChirico for the suggestion and @ben-schwen for the implementation.
+
 ## data.table [v1.18.0](https://github.com/Rdatatable/data.table/milestone/37?closed=1)  23 December 2025
 
 ### BREAKING CHANGE

R/test.data.table.R

@@ -370,10 +370,17 @@ gc_mem = function() {
   # nocov end
 }
 
+# Check if UTF-8 symbols can be represented in native encoding
+# R's parser requires symbol names (PRINTNAME in LANGSXP) to be in native encoding. In non-UTF-8
+# locales, parsing Unicode escapes like \u00FC fails with a warning and substitutes <U+00FC>.
+# Tests using requires_utf8 are skipped when UTF-8 cannot be represented. Using eval(parse(text=...))
+# defers parsing to runtime, allowing the encoding check to run first and avoid source() warnings.
+utf8_check = function(test_str) identical(test_str, enc2native(test_str))
+
 test = function(num, x, y=TRUE,
                 error=NULL, warning=NULL, message=NULL, output=NULL, notOutput=NULL, ignore.warning=NULL,
                 options=NULL, env=NULL,
-                context=NULL) {
+                context=NULL, requires_utf8=FALSE) {
   if (!is.null(env)) {
     old = Sys.getenv(names(env), names=TRUE, unset=NA)
     to_unset = !lengths(env)
@@ -387,6 +394,20 @@ test = function(num, x, y=TRUE,
       Sys.unsetenv(names(old)[!is_preset])
     }, add=TRUE)
   }
+  # Check UTF-8 requirement
+  if (!isFALSE(requires_utf8)) {
+    test_str = if (isTRUE(requires_utf8)) "\u00F1\u00FC\u3093" else requires_utf8 # the default test_str are UTF-8 symbols we found over time, TOOD: harden this default
+    if (!utf8_check(test_str)) {
+      # nocov start
+      last_utf8_skip = get0("last_utf8_skip", parent.frame(), ifnotfound=0, inherits=TRUE)
+      if (num - last_utf8_skip >= 1) {
+        catf("Test %s skipped because required UTF-8 symbols cannot be represented in native encoding.\n", num)
+      }
+      assign("last_utf8_skip", num, parent.frame(), inherits=TRUE)
+      return(invisible(TRUE))
+      # nocov end
+    }
+  }
   # Usage:
   # i) tests that x equals y when both x and y are supplied, the most common usage
   # ii) tests that x is TRUE when y isn't supplied

inst/tests/tests.Rraw

@@ -78,6 +78,7 @@ if (exists("test.data.table", .GlobalEnv, inherits=FALSE)) {
   test = data.table:::test
   uniqlengths = data.table:::uniqlengths
   uniqlist = data.table:::uniqlist
+  utf8_check = data.table:::utf8_check
   warningf = data.table:::warningf
   which_ = data.table:::which_
   which.first = data.table:::which.first
@@ -3569,7 +3570,35 @@ DT[,`:=`(last.x=tail(x,1L),last.x1=tail(x1,1L)),by=y]
 test(1086, class(DT$last.x), c("POSIXct", "POSIXt"))
 test(1087, class(DT$last.x1), "ITime")
 
-# Tests 1088-1093 were non-ASCII. Now in DtNonAsciiTests
+# chmatch on 'unknown' encoding (e.g. as.character(as.symbol("\u00E4")) )falling back to match, #2538 and #4818
+local({
+x1 = c("al\u00E4", "ala", "\u00E4allc", "coep")
+x2 = c("ala", "al\u00E4")
+if (utf8_check(c(x1,x2))) {
+  tstc = function(y) unlist(lapply(y, function(x) as.character(as.name(x))), use.names=FALSE)
+  test(1088.1, chmatch(x1, x2), match(x1, x2)) # should not fallback to "match"
+  test(1088.2, x1 %chin% x2, x1 %in% x2)
+  # change x1 to symbol to character
+  test(1089.1, chmatch(tstc(x1), x2), match(tstc(x1), x2)) # should fallback to match in "x"
+  test(1089.2, tstc(x1) %chin% x2, tstc(x1) %in% x2) # should fallback to match in "x"
+  # change x2 to symbol to character
+  test(1090.1, chmatch(x1,tstc(x2)), match(x1, tstc(x2))) # should fallback to match in "table"
+  test(1090.2, x1 %chin% tstc(x2), x1 %in% tstc(x2))
+  # both are symbols to characters
+  test(1091.1, chmatch(tstc(x1), tstc(x2)), match(tstc(x1), tstc(x2))) # should fallback to "match" in "x" as well.
+  test(1091.2, tstc(x1) %chin% tstc(x2), tstc(x1) %in% tstc(x2))
+} else cat("Tests 1088-1091 skipped because required UTF-8 symbols cannot be represented in native encoding.\n")
+})
+# for completeness, include test from #2528 of non ascii LHS of := (it could feasibly fail in future due to something other than chmatch)
+
+local(if (utf8_check("\u00E4")) {
+eval(parse(text='  # eval(parse()) defers parsing to runtime; see utf8_check description
+  DT = data.table(pas = c(1:5, NA, 6:10), good = c(1:10, NA))
+  setnames(DT, "pas", "p\u00E4s")
+  test(1092, DT[is.na(p\u00E4s), p\u00E4s := 99L], data.table("p\u00E4s" = c(1:5, 99L, 6:10), good = c(1:10,NA)))
+  test(1093, DT[, p\u00E4s := 34L], data.table("p\u00E4s" = 34L, good=c(1:10,NA)))
+'))
+} else cat("Tests 1092+1093 skipped because required UTF-8 symbols cannot be represented in native encoding.\n"))
 
 # print of unnamed DT with >20 <= 100 rows, #97 (RF#4934)
 DT <- data.table(x=1:25, y=letters[1:25])
@@ -4322,7 +4351,10 @@ test(1162.24, is.sorted(rep(NA_character_, 2)))
 x <- character(0)
 test(1163, last(x), character(0))
 
-# Test 1164 was a non-ASCII test, now in DtNonAsciiTests
+# Bug fix for #5159 - chmatch and character encoding (for some reason this seems to pass the test on a mac as well)
+a = c("a","\u00E4","\u00DF","z")
+au = iconv(a,"UTF8","latin1")
+test(1164.1, requires_utf8=c("\u00E4", "\u00DF"), chmatch(a, au), match(a, au))
 
 # Bug fix for #73 - segfault when rbindlist on empty data.tables
 x <- as.data.table(BOD)
@@ -4608,7 +4640,28 @@ test(1228.4, class(DT), class(DT[, sum(b), by=a]))
 test(1228.5, class(DT), class(DT[a>1, sum(b), by=a]))
 test(1228.6, class(DT), class(DT[a>1, c:=sum(b), by=a]))
 
-# test 1229 was non-ASCII, now in package DtNonAsciiTests
+# savetl_init error after error, in v1.9.2, thanks Arun
+DT = data.table(x=1:5, y=10:6)
+test(1229.1, DT[forderv(DT, -1)], error="non-existing column")
+test(1229.2, setkey(DT), data.table(x=1:5, y=10:6, key="x,y"))
+# umlaut in column names (red herring I think, but testing anyway)
+local(if (utf8_check("\u00fc")) {
+  eval(parse(text = '  # eval(parse()) defers parsing to runtime; see utf8_check description
+    sentEx = data.table(abend = c(1, 1, 0, 0, 2),
+                      aber = c(0, 1, 0, 0, 0),
+                      "\u00FCber" = c(1, 0, 0, 0, 0),
+                      "\u00FCberall" = c(0, 0, 0, 0, 0),
+                      "\u00FCberlegt" = c(0, 0, 0, 0, 0),
+                      ID = structure(c(1L, 1L, 2L, 2L, 2L), .Label = c("0019", "0021"), class = "factor"),
+                      abgeandert = c(1, 1, 1, 0, 0),
+                      abgebildet = c(0, 0, 1, 1, 0),
+                      abgelegt = c(0, 0, 0, 0, 3))
+    test(1229.3, sentEx[, lapply(.SD, sum), by=ID], data.table(ID=factor(c("0019","0021")), abend=c(2,2), aber=c(1,0), "\u00FCber"=c(1,0),
+         "\u00FCberall"=c(0,0), "\u00FCberlegt" = c(0,0), abgeandert=c(2,1), abgebildet = c(0,2), abgelegt=c(0,3)))
+  '))
+} else {
+  cat("Test 1229.3 skipped because required UTF-8 symbols cannot be represented in native encoding.\n")
+})
 
 # Test that ad hoc by detects if ordered and dogroups switches to memcpy if contiguous, #1050
 DT = data.table(a=1:3,b=1:6,key="a")
@@ -7901,10 +7954,8 @@ test(1547, foo(1L, 5L, a=2L, "c"), c("2", "c"))
 
 # Fix for encoding issues in windows, #563
 f = testDir("issue_563_fread.txt")
-ans1 <- fread(f, sep=",", header=TRUE)
-ans2 <- fread(f, sep=",", header=TRUE, encoding="UTF-8")
-test(1548.1, unique(unlist(lapply(ans1, Encoding))), "unknown")
-test(1548.2, unique(unlist(lapply(ans2, Encoding))), "UTF-8")
+test(1548.1, requires_utf8=TRUE, unique(unlist(lapply(fread(f, sep=",", header=TRUE), Encoding))), "unknown")
+test(1548.2, requires_utf8=TRUE, unique(unlist(lapply(fread(f, sep=",", header=TRUE, encoding="UTF-8"), Encoding))), "UTF-8")
 
 # 1549 moved to benchmark.Rraw, #5517
 
@@ -17654,12 +17705,9 @@ test(2194.4, endsWithAny(letters, 'e'), error="Internal error.*types or lengths
 test(2194.5, endsWithAny(NA_character_, 'a'), FALSE)
 test(2194.6, endsWithAny(character(), 'a'), error="Internal error.*types or lengths incorrect")
 # file used in encoding tests
-txt = readLines(testDir("issue_563_fread.txt"))
-local(if (eval(utf8_check_expr)) {
-  test(2194.7, endsWithAny(txt, 'B'), error="Internal error.*types or lengths incorrect") # txt is length 5
-} else {
-  cat("Test 2194.7 skipped because it needs a UTF-8 locale.\n")
-})
+needed_chars = c("\u0105", "\u017E", "\u016B", "\u012F", "\u0173", "\u0117", "\u0161", "\u0119")
+txt = parse(text='readLines(testDir("issue_563_fread.txt"))')
+test(2194.7, requires_utf8=needed_chars, endsWithAny(eval(txt), 'B'), error="Internal error.*types or lengths incorrect") # txt is length 5
 test(2194.8, endsWith('abcd', 'd'), error="Internal error.*use endsWithAny")
 
 # uniqueN(x, by=character()) was internal error, #4594
@@ -18651,12 +18699,14 @@ test(2252.2, dt[, let(b=2L)], error = "\\[ was called on a data.table.*not data.
 rm(.datatable.aware)
 
 # tests for trunc.char handling wide characters #5096
-local(if (eval(utf8_check_expr)) {
-  accented_a = "\u0061\u0301"
-  ja_ichi = "\u4E00"
-  ja_ni = "\u4E8C"
-  ja_ko = "\u3053"
-  ja_n = "\u3093"
+local({
+accented_a = "\u0061\u0301"
+ja_ichi = "\u4E00"
+ja_ni = "\u4E8C"
+ja_ko = "\u3053"
+ja_n = "\u3093"
+nc = c(accented_a, ja_ichi, ja_ni, ja_ko, ja_n)
+if (utf8_check(nc)) {
   dots = "..."
   clean_regex = "^\\d+:\\s+" # removes row numbering from beginning of output
   # Tests for combining character latin a and acute accent, single row
@@ -18703,7 +18753,7 @@ local(if (eval(utf8_check_expr)) {
   test(2253.20, options=list(datatable.prettyprint.char = 1L), data.table(a = c("abc", NA)), output="      a\n1: a...\n2: <NA>")
 } else {
   cat("Tests 2253* skipped because they need a UTF-8 locale.\n")
-})
+}})
 
 # allow 1-D matrix in j for consistency, #783
 DT=data.table(a = rep(1:2, 3), b = 1:6)
@@ -20859,18 +20909,20 @@ x = data.table(a=1, b=2L)
 y = data.table(c=1.5, d=1L)
 test(2297.31, y[x, on=.(c == a, d == a), nomatch=NULL], output="Empty data.table (0 rows and 3 cols): c,d,b")
 
-local(if (eval(utf8_check_expr)) {
+local(if (utf8_check(c("\u00e4", "\u00f6", "\u00fc"))) {
   # rbindlist(l, use.names=TRUE) should handle different colnames encodings #5452
   x = data.table(a = 1, b = 2, c = 3)
   y = data.table(x = 4, y = 5, z = 6)
   # a-umlaut, o-umlaut, u-umlaut
-  setnames(x , c("\u00e4", "\u00f6", "\u00fc"))
-  setnames(y , iconv(c("\u00f6", "\u00fc", "\u00e4"), from = "UTF-8", to = "latin1"))
-  test(2298.1, rbindlist(list(x,y), use.names=TRUE), data.table("\u00e4"=c(1,6), "\u00f6"=c(2,4), "\u00fc"=c(3,5)))
-  test(2298.2, rbindlist(list(y,x), use.names=TRUE), data.table("\u00f6"=c(4,2), "\u00fc"=c(5,3), "\u00e4"=c(6,1)))
-  set(y, j="\u00e4", value=NULL)
-  test(2298.3, rbindlist(list(x,y), use.names=TRUE, fill=TRUE), data.table("\u00e4"=c(1,NA), "\u00f6"=c(2,4), "\u00fc"=c(3,5)))
-  test(2298.4, rbindlist(list(y,x), use.names=TRUE, fill=TRUE), data.table("\u00f6"=c(4,2),  "\u00fc"=c(5,3), "\u00e4"=c(NA,1)))
+  eval(parse(text = '  # eval(parse()) defers parsing to runtime; see utf8_check description
+    setnames(x , c("\u00e4", "\u00f6", "\u00fc"))
+    setnames(y , iconv(c("\u00f6", "\u00fc", "\u00e4"), from = "UTF-8", to = "latin1"))
+    test(2298.1, rbindlist(list(x,y), use.names=TRUE), data.table("\u00e4"=c(1,6), "\u00f6"=c(2,4), "\u00fc"=c(3,5)))
+    test(2298.2, rbindlist(list(y,x), use.names=TRUE), data.table("\u00f6"=c(4,2), "\u00fc"=c(5,3), "\u00e4"=c(6,1)))
+    set(y, j="\u00e4", value=NULL)
+    test(2298.3, rbindlist(list(x,y), use.names=TRUE, fill=TRUE), data.table("\u00e4"=c(1,NA), "\u00f6"=c(2,4), "\u00fc"=c(3,5)))
+    test(2298.4, rbindlist(list(y,x), use.names=TRUE, fill=TRUE), data.table("\u00f6"=c(4,2),  "\u00fc"=c(5,3), "\u00e4"=c(NA,1)))
+  '))
 } else {
   cat("Tests 2298.* skipped because they need a UTF-8 locale.\n")
 })
@@ -21636,13 +21688,13 @@ if (base::getRversion() >= "4.3.0") { ## follow up of #7213, see #7321
 }
 
 # fwrite: allow dec=',' with single column, #7227
-test(2337.1, fwrite(data.table(1), dec=","), NULL)
+test(2337.1, fwrite(data.table(1), dec=","), output = "V1\n1")
 if (base::getRversion() >= "4.0.0") { # rely on stopifnot(named = ...) for correct message
   test(2337.2, fwrite(data.table(0.1, 0.2), dec=",", sep=","), error = "dec and sep must be distinct")
 }
-test(2337.3, is.null(fwrite(data.table(c(0.1, 0.2)), dec=",", sep="\t")))
-test(2337.4, is.null(fwrite(data.table(a=numeric(), b=numeric()), dec=",", sep=",")))
-test(2337.5, is.null(fwrite(data.table(a=numeric()), dec=",", sep=",")))
+test(2337.3, fwrite(data.table(c(0.1, 0.2)), dec=",", sep="\t"), output = "V1\n0,1\n0,2")
+test(2337.4, fwrite(data.table(a=numeric(), b=numeric()), dec=",", sep=","), output = "a,b")
+test(2337.5, fwrite(data.table(a=numeric()), dec=",", sep=","), output = "a")
 
 # 2864 force decimal points for whole numbers in numeric columns
 dd = data.table(x=c(1, 2, 3))

man/test.Rd

@@ -8,7 +8,8 @@
 test(num, x, y = TRUE,
      error = NULL, warning = NULL, message = NULL,
      output = NULL, notOutput = NULL, ignore.warning = NULL,
-     options = NULL, env = NULL, context = NULL)
+     options = NULL, env = NULL, context = NULL,
+     requires_utf8 = FALSE)
 }
 \arguments{
 \item{num}{ A unique identifier for a test, helpful in identifying the source of failure when testing is not working. Currently, we use a manually-incremented system with tests formatted as \code{n.m}, where essentially \code{n} indexes an issue and \code{m} indexes aspects of that issue. For the most part, your new PR should only have one value of \code{n} (scroll to the end of \code{inst/tests/tests.Rraw} to see the next available ID) and then index the tests within your PR by increasing \code{m}. Note -- \code{n.m} is interpreted as a number, so \code{123.4} and \code{123.40} are actually the same -- please \code{0}-pad as appropriate. Test identifiers are checked to be in increasing order at runtime to prevent duplicates being possible. }
@@ -23,6 +24,7 @@ test(num, x, y = TRUE,
 \item{options}{ A named list of options to set for the duration of the test. Any code evaluated during this call to \code{test()} (usually, \code{x}, or maybe \code{y}) will run with the named options set, and the original options will be restored on return. This is a named list since different options can have different types in general, but in typical usage, only one option is set at a time, in which case a named vector is also accepted. }
 \item{env}{ A named list of environment variables to set for the duration of the test, much like \code{options}. A list entry set to \code{NULL} will unset (i.e., \code{\link{Sys.unsetenv}}) the corresponding variable. }
 \item{context}{ String, default \code{NULL}. Used to provide context where this is useful, e.g. in a test run in a loop where we can't just search for the test number. }
+\item{requires_utf8}{ \code{FALSE} (default), \code{TRUE}, or a character string. When set, the test is skipped if UTF-8 characters cannot be represented in the native encoding. Use \code{TRUE} for default UTF-8 test characters or provide a custom string of test characters. }
 }
 \note{
    \code{NA_real_} and \code{NaN} are treated as equal, use \code{identical} if distinction is needed. See examples below.