Implement alternative to lazy generations:

* only the last generation can be lazy
* depend on the '--lazy-generation' flag to be set

1 files changed, 14 insertions, 4 deletions

diff --git a/tests/user-envs.sh b/tests/user-envs.sh
index ad15ddc3e441..6b290e50189e 100644
--- a/tests/user-envs.sh
+++ b/tests/user-envs.sh
@@ -99,14 +99,24 @@ if nix-env -q '*' | grep -q bar; then false; fi
 nix-env --list-generations
 test "$(nix-env --list-generations | wc -l)" -eq 7
 
-# Doing the same operation twice should result in the same generation, not an
-# additional one. At this point we just brought back foo. Installing it again
-# should not create a new generation.
+# Doing the same operation twice results in the same generation, but creates an
+# additional one. At this point we just brought back foo.
+
 nix-env -i foo
 
 # Count generations.
 nix-env --list-generations
-test "$(nix-env --list-generations | wc -l)" -eq 7
+test "$(nix-env --list-generations | wc -l)" -eq 8
+
+# Now, doing that again but passing the --lazy-generations flag will not
+# create a new generation.
+
+nix-env -i foo --lazy-generation
+
+# Count generations.
+nix-env --list-generations
+test "$(nix-env --list-generations | wc -l)" -eq 8
+
 
 # Switch to a specified generation.
 nix-env --switch-generation 7