Improve testing infrastructure

.github/workflows/test.yml

@@ -2,6 +2,8 @@ name: "Test"
 on:
   pull_request:
   push:
+    branches:
+      - main
 jobs:
   tests:
     strategy:
@@ -11,7 +13,5 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-      with:
-        fetch-depth: 0
-    - uses: cachix/install-nix-action@v23
-    - run: nix-build -A checks.$(nix-instantiate --eval -E '(builtins.currentSystem)')
+    - uses: cachix/install-nix-action@V28
+    - run: nix flake check

.mergify.yml

@@ -0,0 +1,14 @@
+queue_rules:
+  - name: default
+    merge_conditions:
+      - check-success=tests (macos-latest)
+      - check-success=tests (ubuntu-latest)
+    batch_size: 5
+    merge_method: rebase
+pull_request_rules:
+  - name: merge using the merge queue
+    conditions:
+      - base=main
+      - label~=merge-queue|dependencies
+    actions:
+      queue: {}

flake.nix

@@ -5,46 +5,41 @@
 
     let
       forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
-      systems = [ "x86_64-linux" "aarch64-linux" "i686-linux" "x86_64-darwin" ];
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "i686-linux"
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
     in {
 
       overlay = final: prev: {
-
-        nix-serve = with final; stdenv.mkDerivation {
-          name = "nix-serve-${self.lastModifiedDate}";
-
-          buildInputs = [ perl nixVersions.latest.perl-bindings perlPackages.Plack perlPackages.Starman perlPackages.DBDSQLite ];
-
-          unpackPhase = "true";
-
-          installPhase =
-            ''
-              mkdir -p $out/libexec/nix-serve
-              cp ${./nix-serve.psgi} $out/libexec/nix-serve/nix-serve.psgi
-
-              mkdir -p $out/bin
-              cat > $out/bin/nix-serve <<EOF
-              #! ${stdenv.shell}
-              PERL5LIB=$PERL5LIB \
-              NIX_REMOTE="\''${NIX_REMOTE:-auto?path-info-cache-size=0}" \
-              exec ${perlPackages.Starman}/bin/starman --preload-app $out/libexec/nix-serve/nix-serve.psgi "\$@"
-              EOF
-              chmod +x $out/bin/nix-serve
-            '';
+        nix-serve = final.pkgs.callPackage ./package.nix {
+          inherit self;
+          nix = final.nixVersions.git;
         };
-
       };
 
-      packages = forAllSystems (system: {
-        nix-serve = (import nixpkgs { inherit system; overlays = [ self.overlay ]; }).nix-serve;
+      packages = forAllSystems (system: let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in {
+        nix-serve = nixpkgs.legacyPackages.${system}.callPackage ./package.nix {
+          inherit self;
+          nix = pkgs.nixVersions.git;
+        };
       });
 
       defaultPackage = forAllSystems (system: self.packages.${system}.nix-serve);
 
-      checks = forAllSystems (system: {
+      checks = forAllSystems (system: let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in {
         build = self.defaultPackage.${system};
-        # FIXME: add a proper test.
+      } // nixpkgs.lib.optionalAttrs (pkgs.stdenv.isLinux) {
+        nixos-test = pkgs.callPackage ./nixos-test.nix {
+          nix-serve = self.defaultPackage.${system};
+        };
       });
-
     };
 }

nix-serve.psgi

@@ -64,7 +64,7 @@ my $app = sub {
         return [404, ['Content-Type' => 'text/plain'], ["Incorrect NAR hash. Maybe the path has been recreated.\n"]]
             unless $narHash eq "sha256:$expectedNarHash";
         my $fh = new IO::Handle;
-        open $fh, "-|", "nix", "dump-path", "--", $storePath;
+        open $fh, "-|", "nix", "--extra-experimental-features", "nix-command", "dump-path", "--", $storePath;
         return [200, ['Content-Type' => 'text/plain', 'Content-Length' => $narSize], $fh];
     }
 
@@ -75,14 +75,14 @@ my $app = sub {
         return [404, ['Content-Type' => 'text/plain'], ["No such path.\n"]] unless $storePath;
         my ($deriver, $narHash, $time, $narSize, $refs) = $store->queryPathInfo($storePath, 1) or die;
         my $fh = new IO::Handle;
-        open $fh, "-|", "nix", "dump-path", "--", $storePath;
+        open $fh, "-|", "nix", "--extra-experimental-features", "nix-command", "dump-path", "--", $storePath;
         return [200, ['Content-Type' => 'text/plain', 'Content-Length' => $narSize], $fh];
     }
 
     elsif ($path =~ /^\/log\/([0-9a-z]+-[0-9a-zA-Z\+\-\.\_\?\=]+)/) {
         my $storePath = "$Nix::Config::storeDir/$1";
         my $fh = new IO::Handle;
-        open $fh, "-|", "nix", "log", $storePath;
+        open $fh, "-|", "nix", "--extra-experimental-features", "nix-command", "log", $storePath;
         return [200, ['Content-Type' => 'text/plain' ], $fh];
     }
 

nixos-test.nix

@@ -0,0 +1,26 @@
+{ hello, testers, nix-serve }:
+
+testers.runNixOSTest {
+  name = "nix-serve";
+  nodes.machine =
+    { pkgs, ... }:
+    {
+      services.nix-serve.enable = true;
+      services.nix-serve.package = nix-serve;
+      environment.systemPackages = [
+        pkgs.hello
+      ];
+    };
+  testScript =
+    let
+      pkgHash = builtins.head (builtins.match "${builtins.storeDir}/([^-]+).+" (toString hello));
+    in
+    ''
+      start_all()
+      machine.wait_for_unit("nix-serve.service")
+      machine.wait_for_open_port(5000)
+      machine.succeed(
+          "curl --fail -g http://0.0.0.0:5000/nar/${pkgHash}.nar -o /tmp/hello.nar"
+      )
+    '';
+}

package.nix

@@ -0,0 +1,35 @@
+{
+  stdenv,
+  perl,
+  perlPackages,
+  nix,
+  self,
+}:
+
+stdenv.mkDerivation {
+  name = "nix-serve-${self.lastModifiedDate}";
+
+  buildInputs = [
+    perl
+    nix.perl-bindings
+    perlPackages.Plack
+    perlPackages.Starman
+    perlPackages.DBDSQLite
+  ];
+
+  unpackPhase = "true";
+
+  installPhase = ''
+    mkdir -p $out/libexec/nix-serve
+    cp ${./nix-serve.psgi} $out/libexec/nix-serve/nix-serve.psgi
+
+    mkdir -p $out/bin
+    cat > $out/bin/nix-serve <<EOF
+    #! ${stdenv.shell}
+    PERL5LIB=$PERL5LIB \
+    NIX_REMOTE="\''${NIX_REMOTE:-auto?path-info-cache-size=0}" \
+    exec ${perlPackages.Starman}/bin/starman --preload-app $out/libexec/nix-serve/nix-serve.psgi "\$@"
+    EOF
+    chmod +x $out/bin/nix-serve
+  '';
+}