Add ci derivation

overlay.nix

@@ -265,6 +265,10 @@ let
 #      hwloc = callPackage ./test/bugs/hwloc.nix { };
       sigsegv = callPackage ./test/reproducers/sigsegv.nix { };
     };
+
+    ci = import ./test/ci.nix {
+      inherit self super bsc callPackage;
+    };
   });
 
 in

test/ci.nix

@@ -0,0 +1,31 @@
+{ self, super, bsc, callPackage }:
+
+let
+  stdenv = self.stdenv;
+in
+
+stdenv.mkDerivation rec {
+  name = "ci";
+  src = ./ci.nix;
+  dontUnpack = true;
+
+  # Just build some packages
+  buildInputs = with bsc; [
+    extrae
+  ];
+
+  buildPhase = ''
+    if [ -e /boot ]; then
+      echo Build is NOT under chroot
+      echo This is the content of / :
+      ls -l /
+      exit 1
+    fi
+
+    echo "OK: Build is under chroot"
+  '';
+
+  installPhase = ''
+    touch $out
+  '';
+}