tests: fix negative asserts with grep not working

Using `grep -v` without `-z` will return 0 even if there is a match
found as all the non-matching lines will be matched. Instead of using
`grep -vqz`, `(! grep ...)` is more readable.

The brackets are necessary as `! grep` will not trigger `set -e`[0], so we
run it inside a subshell to use its non-zero exit code.

[0]: https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html#The-Set-Builtin

pkgs/darwin-installer/default.nix

@@ -118,7 +118,7 @@ stdenv.mkDerivation {
         test -e /etc/static
         echo >&2 "checking profile"
         cat /etc/profile
-        grep -v nix-daemon.sh /etc/profile
+        (! grep nix-daemon.sh /etc/profile)
         echo >&2 "checking /run/current-system"
         readlink /run
         test -e /run

tests/programs-zsh.nix

@@ -34,7 +34,7 @@
      echo >&2 "checking compinit in /etc/zshrc"
      grep 'autoload -U compinit && compinit' ${config.out}/etc/zshrc
      echo >&2 "checking bashcompinit in /etc/zshrc"
-     grep -vq 'bashcompinit' ${config.out}/etc/zshrc
+     (! grep 'bashcompinit' ${config.out}/etc/zshrc)
 
      echo >&2 "checking zprofile.d in /etc/zprofile"
      grep 'source /etc/zprofile.d/\*.conf' ${config.out}/etc/zprofile

tests/users-groups.nix

@@ -28,37 +28,37 @@
     grep "dscl . -create ${lib.escapeShellArg "/Groups/foo"} PrimaryGroupID 42000" ${config.out}/activate
     grep "dscl . -create ${lib.escapeShellArg "/Groups/foo"} RealName ${lib.escapeShellArg "Foo group"}" ${config.out}/activate
     grep "dscl . -create ${lib.escapeShellArg "/Groups/created.group"} PrimaryGroupID 42001" ${config.out}/activate
-    grep -qv "dscl . -delete ${lib.escapeShellArg "/Groups/created.group"}" ${config.out}/activate
+    (! grep "dscl . -delete ${lib.escapeShellArg "/Groups/created.group"}" ${config.out}/activate)
 
     # checking group deletion in /activate
     grep "dscl . -delete ${lib.escapeShellArg "/Groups/deleted.group"}" ${config.out}/activate
-    grep -qv "dscl . -create ${lib.escapeShellArg "/Groups/deleted.group"}" ${config.out}/activate
+    (! grep "dscl . -create ${lib.escapeShellArg "/Groups/deleted.group"}" ${config.out}/activate)
 
     echo "checking group membership in /activate" >&2
     grep "dscl . -create ${lib.escapeShellArg "/Groups/foo"} GroupMembership ${lib.escapeShellArgs [ "admin" "foo" ]}" ${config.out}/activate
     grep "dscl . -create ${lib.escapeShellArg "/Groups/created.group"} GroupMembership" ${config.out}/activate
 
     # checking unknown group in /activate
-    grep -qv "dscl . -create ${lib.escapeShellArg "/Groups/unknown.group"}" ${config.out}/activate
+    (! grep "dscl . -create ${lib.escapeShellArg "/Groups/unknown.group"}" ${config.out}/activate)
-    grep -qv "dscl . -delete ${lib.escapeShellArg "/Groups/unknown.group"}" ${config.out}/activate
+    (! grep "dscl . -delete ${lib.escapeShellArg "/Groups/unknown.group"}" ${config.out}/activate)
 
     # checking user creation in /activate
     grep "sysadminctl -addUser ${lib.escapeShellArgs [ "foo" "-UID" 42000 "-GID" 42000 "-fullName" "Foo user" "-home" "/Users/foo" "-shell" "/run/current-system/sw/bin/bash" ]}" ${config.out}/activate
     grep "createhomedir -cu ${lib.escapeShellArg "foo"}" ${config.out}/activate
     grep "sysadminctl -addUser ${lib.escapeShellArgs [ "created.user" "-UID" 42001 ]} .* ${lib.escapeShellArgs [ "-shell" "/sbin/nologin" ]}" ${config.out}/activate
-    grep -qv "deleteUser ${lib.escapeShellArg "created.user"}" ${config.out}/activate
+    (! grep "deleteUser ${lib.escapeShellArg "created.user"}" ${config.out}/activate)
-    grep -qv "deleteUser ${lib.escapeShellArg "created.user"}" ${config.out}/activate
+    (! grep "deleteUser ${lib.escapeShellArg "created.user"}" ${config.out}/activate)
 
     # checking user properties always get updated in /activate
     grep "dscl . -create ${lib.escapeShellArg "/Users/foo"} UserShell ${lib.escapeShellArg "/run/current-system/sw/bin/bash"}" ${config.out}/activate
 
     # checking user deletion in /activate
     grep "deleteUser ${lib.escapeShellArg "deleted.user"}" ${config.out}/activate
-    grep -qv "sysadminctl -addUser ${lib.escapeShellArg "deleted.user"}" ${config.out}/activate
+    (! grep "sysadminctl -addUser ${lib.escapeShellArg "deleted.user"}" ${config.out}/activate)
 
     # checking unknown user in /activate
-    grep -qv "sysadminctl -addUser ${lib.escapeShellArg "unknown.user"}" ${config.out}/activate
+    (! grep "sysadminctl -addUser ${lib.escapeShellArg "unknown.user"}" ${config.out}/activate)
-    grep -qv "deleteUser ${lib.escapeShellArg "unknown.user"}" ${config.out}/activate
+    (! grep "deleteUser ${lib.escapeShellArg "unknown.user"}" ${config.out}/activate)
 
     set +v
   '';