Add a test for the remote caching of CA derivations

tests/ca/substitute.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+# Ensure that binary substitution works properly with ca derivations
+
+source common.sh
+
+export REMOTE_STORE=file://$TEST_ROOT/binary_cache
+
+buildDrvs () {
+    nix --experimental-features 'nix-command ca-derivations ca-references' build --file ./content-addressed.nix -L --no-link "$@"
+}
+
+# Populate the remote cache
+buildDrvs --post-build-hook ../push-to-store.sh
+
+# Restart the build on an empty store, ensuring that we don't build
+clearStore
+buildDrvs --substitute --substituters $REMOTE_STORE --no-require-sigs|& \
+    (! grep -q Building)
+

tests/local.mk

@@ -38,7 +38,8 @@ nix_tests = \
   flakes.sh \
   build.sh \
   ca/build.sh \
-  ca/nix-copy.sh
+  ca/nix-copy.sh \
+  ca/substitute.sh
   # parallel.sh
   # build-remote-content-addressed-fixed.sh \