diff --git a/tests/installer.nix b/tests/installer.nix
index a07beaeb1e6..74e0149feec 100644
--- a/tests/installer.nix
+++ b/tests/installer.nix
@@ -82,6 +82,7 @@ let
 
       virtualisation.writableStore = true;
       virtualisation.pathsInNixDB = channelContents;
+      virtualisation.memorySize = 512;
     };
 
   channelContents = [ pkgs.hello.src pkgs.rlwrap ];