lib.lists: Use builtins.groupBy for lib.groupBy

builtins.groupBy is much more performant. It was introduced in
https://github.com/NixOS/nix/pull/5715

1 files changed, 17 insertions, 1 deletions

diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix
index c4a34369f50..c2e76f18d95 100644
--- a/lib/tests/misc.nix
+++ b/lib/tests/misc.nix
@@ -781,6 +781,22 @@ runTests {
       "a2-b"
       "_bc'de"
     ];
-    expected = "\".\".foo.\"2\".a2-b._bc'de";
+    expected = ''".".foo."2".a2-b._bc'de'';
+  };
+
+  testGroupBy = {
+    expr = groupBy (n: toString (mod n 5)) (range 0 16);
+    expected = {
+      "0" = [ 0 5 10 15 ];
+      "1" = [ 1 6 11 16 ];
+      "2" = [ 2 7 12 ];
+      "3" = [ 3 8 13 ];
+      "4" = [ 4 9 14 ];
+    };
+  };
+
+  testGroupBy' = {
+    expr = groupBy' builtins.add 0 (x: boolToString (x > 2)) [ 5 1 2 3 4 ];
+    expected = { false = 3; true = 12; };
   };
 }