Fix test relying on deprecated behavior comparing language objects (#5986)

* fix test relying on deprecated behavior comparing language objects

* NEWS

Author: MichaelChirico

NEWS.md

@@ -42,6 +42,8 @@
 
 6. `dcast()` message about `fun.aggregate` defaulting to `length()` when aggregation is necessary, which could be confusing if duplicates were unexpected, does better explaining the behavior and suggesting alternatives, [#5217](https://github.com/Rdatatable/data.table/issues/5217). Thanks @MichaelChirico for the suggestion and @Nj221102 for the fix.
 
+7. Updated a test relying on `>` working for comparing language objects to a string, which will be deprecated by R, [#5977](https://github.com/Rdatatable/data.table/issues/5977); no user-facing effect. Thanks to R-core for continuously improving the language.
+
 # data.table [v1.15.0](https://github.com/Rdatatable/data.table/milestone/29)  (30 Jan 2024)
 
 ## BREAKING CHANGE

inst/tests/tests.Rraw

@@ -1764,7 +1764,7 @@ test(578, X[Y,verbose=TRUE], data.table(a=c("D","B"), v=c(4L,2L)),  # no key bec
 
 # Test that logical i in set() returns helpful error
 DT = data.table(a=1:3,b=4:6)
-test(580, set(DT,a<3,"b",0L), error="simply wrap with which(), and take the which() outside the loop if possible for efficiency")
+test(580, set(DT,DT$a<3,"b",0L), error="simply wrap with which(), and take the which() outside the loop if possible for efficiency")
 
 # Test by on empty tables (and when i returns no rows), #1945
 DT = data.table(a=1:3,v=1:6)