firefox: Add test references

pkgs/applications/networking/browsers/firefox/common.nix

@@ -1,6 +1,6 @@
 { pname, ffversion, meta, updateScript ? null
 , src, unpackPhase ? null, patches ? []
-, extraNativeBuildInputs ? [], extraConfigureFlags ? [], extraMakeFlags ? [] }:
+, extraNativeBuildInputs ? [], extraConfigureFlags ? [], extraMakeFlags ? [], tests ? [] }:
 
 { lib, stdenv, pkg-config, pango, perl, python3, zip
 , libjpeg, zlib, dbus, dbus-glib, bzip2, xorg
@@ -351,6 +351,7 @@ buildStdenv.mkDerivation ({
     inherit gssSupport;
     inherit execdir;
     inherit browserName;
+    inherit tests;
   } // lib.optionalAttrs gtk3Support { inherit gtk3; };
 
   hardeningDisable = [ "format" ]; # -Werror=format-security

pkgs/applications/networking/browsers/firefox/packages.nix

@@ -1,4 +1,4 @@
-{ stdenv, lib, callPackage, fetchurl, fetchpatch }:
+{ stdenv, lib, callPackage, fetchurl, fetchpatch, nixosTests }:
 
 let
   common = opts: callPackage (import ./common.nix opts) {};
@@ -23,6 +23,7 @@ rec {
                                              # not in `badPlatforms` because cross-compilation on 64-bit machine might work.
       license = lib.licenses.mpl20;
     };
+    tests = [ nixosTests.firefox ];
     updateScript = callPackage ./update.nix {
       attrPath = "firefox-unwrapped";
       versionKey = "ffversion";
@@ -47,6 +48,7 @@ rec {
                                              # not in `badPlatforms` because cross-compilation on 64-bit machine might work.
       license = lib.licenses.mpl20;
     };
+    tests = [ nixosTests.firefox-esr ];
     updateScript = callPackage ./update.nix {
       attrPath = "firefox-esr-78-unwrapped";
       versionKey = "ffversion";