Add a test for the binary cache substituter

tests/Makefile.am

@@ -9,7 +9,8 @@ TESTS = init.sh hash.sh lang.sh add.sh simple.sh dependencies.sh \
   gc-runtime.sh install-package.sh check-refs.sh filter-source.sh \
   remote-store.sh export.sh export-graph.sh negative-caching.sh \
   binary-patching.sh timeout.sh secure-drv-outputs.sh nix-channel.sh \
-  multiple-outputs.sh import-derivation.sh fetchurl.sh optimise-store.sh
+  multiple-outputs.sh import-derivation.sh fetchurl.sh optimise-store.sh \
+  binary-cache.sh
 
 XFAIL_TESTS =
 

tests/binary-cache.sh

@@ -0,0 +1,19 @@
+source common.sh
+
+clearStore
+
+cacheDir=$TEST_ROOT/binary-cache
+rm -rf $cacheDir
+
+outPath=$(nix-build dependencies.nix --no-out-link)
+
+nix-push --dest $cacheDir $outPath
+
+clearStore
+
+rm -f $NIX_STATE_DIR/binary-cache*
+
+NIX_BINARY_CACHES="file://$cacheDir" nix-store -r $outPath
+
+nix-store --check-validity $outPath
+nix-store -qR $outPath | grep input-2