diff --git a/tests/ca/gc.sh b/tests/ca/gc.sh
new file mode 100755
index 000000000..e4f9857d6
--- /dev/null
+++ b/tests/ca/gc.sh
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+# Ensure that garbage collection works properly with ca derivations
+
+source common.sh
+
+sed -i 's/experimental-features .*/& ca-derivations ca-references/' "$NIX_CONF_DIR"/nix.conf
+
+export NIX_TESTS_CA_BY_DEFAULT=1
+
+cd ..
+source gc.sh
diff --git a/tests/config.nix.in b/tests/config.nix.in
index a57a8c596..9b00d9ddb 100644
--- a/tests/config.nix.in
+++ b/tests/config.nix.in
@@ -1,3 +1,12 @@
+let
+  contentAddressedByDefault = builtins.getEnv "NIX_TESTS_CA_BY_DEFAULT" == "1";
+  caArgs = if contentAddressedByDefault then {
+    __contentAddressed = true;
+    outputHashMode = "recursive";
+    outputHashAlgo = "sha256";
+  } else {};
+in
+
 rec {
   shell = "@bash@";
 
@@ -15,4 +24,4 @@ rec {
       PATH = path;
     } // removeAttrs args ["builder" "meta"])
     // { meta = args.meta or {}; };
-}
+} // caArgs
diff --git a/tests/local.mk b/tests/local.mk
index 59eb4eb0f..e40178b80 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -2,6 +2,7 @@ nix_tests = \
   hash.sh lang.sh add.sh simple.sh dependencies.sh \
   config.sh \
   gc.sh \
+  ca/gc.sh \
   gc-concurrent.sh \
   gc-auto.sh \
   referrers.sh user-envs.sh logging.sh nix-build.sh misc.sh fixed.sh \