adding an atime test case; groupby with dogroups (R expression) #PR4558 (#6288)

Co-authored-by: Toby Dylan Hocking <tdhock5@gmail.com>

Author: DorisAmoakohene

.ci/atime/tests.R

@@ -121,6 +121,24 @@ test.list <- atime::atime_test_list(
     Slow = "c4a2085e35689a108d67dacb2f8261e4964d7e12", # Parent of the first commit in the PR that fixes the issue (https://github.com/Rdatatable/data.table/commit/7cc4da4c1c8e568f655ab5167922dcdb75953801)
     Fast = "1872f473b20fdcddc5c1b35d79fe9229cd9a1d15"), # Last commit in the PR that fixes the issue (https://github.com/Rdatatable/data.table/pull/5427/commits)
 
+  # Issue reported in: https://github.com/Rdatatable/data.table/issues/4200
+  # To be fixed in: https://github.com/Rdatatable/data.table/pull/4558
+  "DT[by] fixed in #4558" = atime::atime_test(
+    N = 10^seq(1, 20),
+    setup = {
+      d <- data.table(
+        id3 = sample(c(seq.int(N*0.9), sample( N*0.9, N*0.1, TRUE))),
+        v1 = sample(5L, N, TRUE),
+        v2 = sample(5L, N, TRUE)
+      )
+    },
+    expr = {
+      expr=data.table:::`[.data.table`(d, , max(v1) - min(v2), by = id3)
+    },
+    Before = "7a9eaf62ede487625200981018d8692be8c6f134", # Parent of the first commit (https://github.com/Rdatatable/data.table/commit/515de90a6068911a148e54343a3503043b8bb87c) in the PR (https://github.com/Rdatatable/data.table/pull/4164/commits) that introduced the regression
+    Regression = "c152ced0e5799acee1589910c69c1a2c6586b95d", # Parent of the first commit (https://github.com/Rdatatable/data.table/commit/15f0598b9828d3af2eb8ddc9b38e0356f42afe4f) in the PR (https://github.com/Rdatatable/data.table/pull/4558/commits) that fixes the regression
+    Fixed = "f750448a2efcd258b3aba57136ee6a95ce56b302"), # Second commit of the PR (https://github.com/Rdatatable/data.table/pull/4558/commits) that fixes the regression
+
   # Issue with sorting again when already sorted: https://github.com/Rdatatable/data.table/issues/4498
   # Fixed in: https://github.com/Rdatatable/data.table/pull/4501
   "DT[,.SD] improved in #4501" = atime::atime_test(
@@ -136,8 +154,7 @@ test.list <- atime::atime_test_list(
     },
     Fast = "353dc7a6b66563b61e44b2fa0d7b73a0f97ca461", # Close-to-last merge commit in the PR (https://github.com/Rdatatable/data.table/pull/4501/commits) that fixes the issue 
     Slow = "3ca83738d70d5597d9e168077f3768e32569c790", # Circa 2024 master parent of close-to-last merge commit (https://github.com/Rdatatable/data.table/commit/353dc7a6b66563b61e44b2fa0d7b73a0f97ca461) in the PR (https://github.com/Rdatatable/data.table/pull/4501/commits) that fixes the issue 
-    Slower = "cacdc92df71b777369a217b6c902c687cf35a70d" # Circa 2020 parent of the first commit (https://github.com/Rdatatable/data.table/commit/74636333d7da965a11dad04c322c752a409db098) in the PR (https://github.com/Rdatatable/data.table/pull/4501/commits) that fixes the issue 
-  ),
+    Slower = "cacdc92df71b777369a217b6c902c687cf35a70d"), # Circa 2020 parent of the first commit (https://github.com/Rdatatable/data.table/commit/74636333d7da965a11dad04c322c752a409db098) in the PR (https://github.com/Rdatatable/data.table/pull/4501/commits) that fixes the issue 
 
   NULL)
 # nolint end: undesirable_operator_linter.