firefox: extract an overlay common to all tests

tests/modules/programs/firefox/deprecated-native-messenger.nix

@@ -2,35 +2,20 @@
 
 with lib;
 
-lib.mkIf config.test.enableBig {
+{
+  imports = [ ./setup-firefox-mock-overlay.nix ];
+
+  config = lib.mkIf config.test.enableBig {
     programs.firefox = {
       enable = true;
       enableGnomeExtensions = true;
     };
 
-  nixpkgs.overlays = [
-    (self: super: {
-      firefox-unwrapped = pkgs.runCommandLocal "firefox-0" {
-        meta.description = "I pretend to be Firefox";
-        passthru.gtk3 = null;
-      } ''
-        mkdir -p "$out"/{bin,lib}
-        touch "$out/bin/firefox"
-        chmod 755 "$out/bin/firefox"
-      '';
-
-      chrome-gnome-shell =
-        pkgs.runCommandLocal "dummy-chrome-gnome-shell" { } ''
-          mkdir -p $out/lib/mozilla/native-messaging-hosts
-          touch $out/lib/mozilla/native-messaging-hosts/dummy
-        '';
-    })
-  ];
-
     test.asserts.warnings.expected = [''
       Using 'programs.firefox.enableGnomeExtensions' has been deprecated and
       will be removed in the future. Please change to overriding the package
       configuration using 'programs.firefox.package' instead. You can refer to
       its example for how to do this.
     ''];
+  };
 }

tests/modules/programs/firefox/profile-settings.nix

@@ -2,7 +2,10 @@
 
 with lib;
 
-lib.mkIf config.test.enableBig {
+{
+  imports = [ ./setup-firefox-mock-overlay.nix ];
+
+  config = lib.mkIf config.test.enableBig {
     programs.firefox = {
       enable = true;
       profiles.basic.isDefault = true;
@@ -33,7 +36,8 @@ lib.mkIf config.test.enableBig {
             name = "wikipedia";
             tags = [ "wiki" ];
             keyword = "wiki";
-          url = "https://en.wikipedia.org/wiki/Special:Search?search=%s&go=Go";
+            url =
+              "https://en.wikipedia.org/wiki/Special:Search?search=%s&go=Go";
           }
           {
             name = "kernel.org";
@@ -140,20 +144,6 @@ lib.mkIf config.test.enableBig {
       };
     };
 
-  nixpkgs.overlays = [
-    (self: super: {
-      firefox-unwrapped = pkgs.runCommand "firefox-0" {
-        meta.description = "I pretend to be Firefox";
-        preferLocalBuild = true;
-        passthru.gtk3 = null;
-      } ''
-        mkdir -p "$out"/{bin,lib}
-        touch "$out/bin/firefox"
-        chmod 755 "$out/bin/firefox"
-      '';
-    })
-  ];
-
     nmt.script = ''
       assertFileRegex \
         home-path/bin/firefox \
@@ -199,4 +189,5 @@ lib.mkIf config.test.enableBig {
         home-files/.mozilla/firefox/searchWithoutDefault/search.json.mozlz4 \
         ${./profile-settings-expected-search-without-default.json}
     '';
+  };
 }

tests/modules/programs/firefox/setup-firefox-mock-overlay.nix

@@ -0,0 +1,22 @@
+{ pkgs, ... }:
+
+{
+  nixpkgs.overlays = [
+    (self: super: {
+      firefox-unwrapped = pkgs.runCommandLocal "firefox-0" {
+        meta.description = "I pretend to be Firefox";
+        passthru.gtk3 = null;
+      } ''
+        mkdir -p "$out"/{bin,lib}
+        touch "$out/bin/firefox"
+        chmod 755 "$out/bin/firefox"
+      '';
+
+      chrome-gnome-shell =
+        pkgs.runCommandLocal "dummy-chrome-gnome-shell" { } ''
+          mkdir -p $out/lib/mozilla/native-messaging-hosts
+          touch $out/lib/mozilla/native-messaging-hosts/dummy
+        '';
+    })
+  ];
+}

tests/modules/programs/firefox/state-version-19_09.nix

@@ -2,28 +2,18 @@
 
 with lib;
 
-lib.mkIf config.test.enableBig {
+{
+  imports = [ ./setup-firefox-mock-overlay.nix ];
+
+  config = lib.mkIf config.test.enableBig {
     home.stateVersion = "19.09";
 
     programs.firefox.enable = true;
 
-  nixpkgs.overlays = [
-    (self: super: {
-      firefox-unwrapped = pkgs.runCommand "firefox-0" {
-        meta.description = "I pretend to be Firefox";
-        preferLocalBuild = true;
-        passthru.gtk3 = null;
-      } ''
-        mkdir -p "$out"/{bin,lib}
-        touch "$out/bin/firefox"
-        chmod 755 "$out/bin/firefox"
-      '';
-    })
-  ];
-
     nmt.script = ''
       assertFileRegex \
         home-path/bin/firefox \
         MOZ_APP_LAUNCHER
     '';
+  };
 }