diff --git a/tests/linux-sandbox-cert-test.nix b/tests/linux-sandbox-cert-test.nix
index 2b86dad2e..2fc083ea9 100644
--- a/tests/linux-sandbox-cert-test.nix
+++ b/tests/linux-sandbox-cert-test.nix
@@ -1,29 +1,30 @@
-{ fixed-output }:
+{ mode }:
 
 with import ./config.nix;
 
-mkDerivation ({
-  name = "ssl-export";
-  buildCommand = ''
-    # Add some indirection, otherwise grepping into the debug output finds the string.
-    report () { echo CERT_$1_IN_SANDBOX; }
+mkDerivation (
+  {
+    name = "ssl-export";
+    buildCommand = ''
+      # Add some indirection, otherwise grepping into the debug output finds the string.
+      report () { echo CERT_$1_IN_SANDBOX; }
 
-    if [ -f /etc/ssl/certs/ca-certificates.crt ]; then
-      content=$(</etc/ssl/certs/ca-certificates.crt)
-      if [ "$content" == CERT_CONTENT ]; then
-        report present
+      if [ -f /etc/ssl/certs/ca-certificates.crt ]; then
+        content=$(</etc/ssl/certs/ca-certificates.crt)
+        if [ "$content" == CERT_CONTENT ]; then
+          report present
+        fi
+      else
+        report missing
       fi
-    else
-      report missing
-    fi
 
-    # Always fail, because we do not want to bother with fixed-output
-    # derivations being cached, and do not want to compute the right hash.
-    false;
-  '';
-} // (
-  if fixed-output == "fixed-output"
-  then { outputHash = "sha256:0000000000000000000000000000000000000000000000000000000000000000"; }
-  else { }
-))
+      # Always fail, because we do not want to bother with fixed-output
+      # derivations being cached, and do not want to compute the right hash.
+      false;
+    '';
+  } // {
+    fixed-output = { outputHash = "sha256:0000000000000000000000000000000000000000000000000000000000000000"; };
+    normal = { };
+  }.${mode}
+)
 
diff --git a/tests/linux-sandbox.sh b/tests/linux-sandbox.sh
index 45f0ce7a4..f2a77174d 100644
--- a/tests/linux-sandbox.sh
+++ b/tests/linux-sandbox.sh
@@ -11,6 +11,8 @@ requireSandboxSupport
 # otherwise things get complicated (e.g. if it's in /bin, do we need
 # /lib as well?).
 if [[ ! $SHELL =~ /nix/store ]]; then skipTest "Shell is not from Nix store"; fi
+# An alias to automatically bind-mount the $SHELL on nix-build invocations
+nix-sandbox-build () { nix-build --no-out-link --sandbox-paths /nix/store "$@"; }
 
 chmod -R u+w $TEST_ROOT/store0 || true
 rm -rf $TEST_ROOT/store0
@@ -18,7 +20,7 @@ rm -rf $TEST_ROOT/store0
 export NIX_STORE_DIR=/my/store
 export NIX_REMOTE=$TEST_ROOT/store0
 
-outPath=$(nix-build dependencies.nix --no-out-link --sandbox-paths /nix/store)
+outPath=$(nix-sandbox-build dependencies.nix)
 
 [[ $outPath =~ /my/store/.*-dependencies ]]
 
@@ -29,24 +31,28 @@ nix store ls -R -l $outPath | grep foobar
 nix store cat $outPath/foobar | grep FOOBAR
 
 # Test --check without hash rewriting.
-nix-build dependencies.nix --no-out-link --check --sandbox-paths /nix/store
+nix-sandbox-build dependencies.nix --check
 
 # Test that sandboxed builds with --check and -K can move .check directory to store
-nix-build check.nix -A nondeterministic --sandbox-paths /nix/store --no-out-link
+nix-sandbox-build check.nix -A nondeterministic
 
-(! nix-build check.nix -A nondeterministic --sandbox-paths /nix/store --no-out-link --check -K 2> $TEST_ROOT/log)
-if grepQuiet 'error: renaming' $TEST_ROOT/log; then false; fi
+expectStderr 104 nix-sandbox-build check.nix -A nondeterministic --check -K > $TEST_ROOT/log
+grepQuietInverse 'error: renaming' $TEST_ROOT/log
 grepQuiet 'may not be deterministic' $TEST_ROOT/log
 
 # Test that sandboxed builds cannot write to /etc easily
-(! nix-build -E 'with import ./config.nix; mkDerivation { name = "etc-write"; buildCommand = "echo > /etc/test"; }' --no-out-link --sandbox-paths /nix/store)
+expectStderr 100 nix-sandbox-build -E 'with import ./config.nix; mkDerivation { name = "etc-write"; buildCommand = "echo > /etc/test"; }' |
+    grepQuiet "/etc/test: Permission denied"
 
 
 ## Test mounting of SSL certificates into the sandbox
 testCert () {
-    (! nix-build linux-sandbox-cert-test.nix --argstr fixed-output "$2" --no-out-link --sandbox-paths /nix/store --option ssl-cert-file "$3" 2> $TEST_ROOT/log)
-    cat $TEST_ROOT/log
-    grepQuiet "CERT_${1}_IN_SANDBOX" $TEST_ROOT/log
+    expectation=$1 # "missing" | "present"
+    mode=$2        # "normal" | "fixed-output"
+    certFile=$3    # a string that can be the path to a cert file
+    [ "$mode" == fixed-output ] && ret=1 || ret=100
+    expectStderr $ret nix-sandbox-build linux-sandbox-cert-test.nix --argstr mode "$mode" --option ssl-cert-file "$certFile" |
+        grepQuiet "CERT_${expectation}_IN_SANDBOX"
 }
 
 nocert=$TEST_ROOT/no-cert-file.pem