matrix-tuwunel: run tests in debug profile (#528878)

pkgs/by-name/ma/matrix-tuwunel/package.nix

@@ -150,6 +150,8 @@ rustPlatform.buildRustPackage (finalAttrs: {
     libredirect.hook
   ];
 
+  # Make sure tuwunel doesn't try to write to arbitrary
+  # directories or have DNS timeouts during `cargo test`.
   preCheck =
     let
       fakeResolvConf = writeTextFile {
@@ -163,8 +165,17 @@ rustPlatform.buildRustPackage (finalAttrs: {
       export NIX_REDIRECTS="/etc/resolv.conf=${fakeResolvConf}"
       export TUWUNEL_DATABASE_PATH="$(mktemp -d)/smoketest.db"
     '';
+
   doCheck = true;
 
+  # 2026-06-24: Tuwunel has 16 integration tests. Cargo turns each of these
+  # into a separate binary that links in all 110 MB worth of tuwunel.  Linking
+  # 16 big binaries like this takes a really long time and was causing Hydra
+  # to time out the build during `checkPhase`.  So, we run the checks in the
+  # "debug" profile.  This reduces the build+test time on my machine from
+  # 44min to 12min.
+  checkType = "debug";
+
   passthru = {
     rocksdb = rocksdb'; # make used rocksdb version available (e.g., for backup scripts)
     updateScript = nix-update-script { };