Add overlay

doc/getting-started.md

@@ -270,3 +270,41 @@ $ ./result/bin/test-driver
 ```
 
 on your CI.
+
+## Using the Overlay
+
+If you would like to use this testing library with your own nixpkgs, use our
+overlay function.
+
+The overlay function makes all linux distributions available under the attribute
+`pkgs.testers.legacyDistros...`:
+
+```nix
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    nix-vm-test.url = "github:numtide/nix-vm-test";
+  };
+
+  outputs = { self, nixpkgs, nix-vm-test }:
+   let
+     system = "x86_64-linux";
+     pkgs = import nixpkgs {
+       inherit system;
+       overlays = [
+         nix-vm-test.overlays.default
+       ];
+     };
+    in
+      packages.x86_64-linux.mytest = pkgs.testers.legacyDistros.debian."13" {
+        sharedDirs.debDir = {
+          source = "${./.}";
+          target = "/mnt/debdir";
+        };
+        testScript = ''
+          vm.wait_for_unit("multi-user.target")
+          vm.succeed("apt-get -yq install /mnt/debdir/hello.deb")
+        '';
+      };
+}
+```

fedora/default.nix

@@ -5,7 +5,7 @@ let
     inherit (image) hash;
     url = "https://download.fedoraproject.org/pub/fedora/linux/releases/${image.name}";
   };
-  images = lib.mapAttrs (k: v: fetchImage v) imagesJSON.${system};
+  images = lib.mapAttrs (k: v: fetchImage v) (imagesJSON.${system} or {});
   makeVmTestForImage = image: { testScript, sharedDirs, diskSize ? null, extraPathsToRegister ? [ ]}: generic.makeVmTest {
     inherit system testScript sharedDirs;
     image = prepareFedoraImage {

flake.nix

@@ -5,11 +5,22 @@
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
   };
 
-  outputs = { self, nixpkgs, ... }: rec {
-    lib.x86_64-linux = import ./lib.nix {
-      inherit nixpkgs;
+  outputs = { self, nixpkgs, flake-utils }:
+    let
       system = "x86_64-linux";
+      pkgs = import nixpkgs {
+        overlays = [ self.overlays.default ];
+        localSystem = system;
+      };
+    in
+    {
+      lib.${system} = pkgs.testers.legacyDistros;
+
+      checks.${system} = import ./tests {
+        package = pkgs.testers.legacyDistros;
+        inherit pkgs system;
+      };
+
+      overlays.default = import ./overlay.nix;
     };
-    checks.x86_64-linux = import ./tests { package = lib; pkgs = nixpkgs.legacyPackages.x86_64-linux; system = "x86_64-linux"; };
-  };
 }

overlay.nix

@@ -0,0 +1,17 @@
+final: prev:
+
+let
+  inherit (prev) system;
+  generic = import ./generic { inherit (prev) lib; pkgs = final; nixpkgs = prev.path; };
+  ubuntu = prev.callPackage ./ubuntu { inherit generic system; };
+  debian = prev.callPackage ./debian { inherit generic system; };
+  fedora = prev.callPackage ./fedora { inherit generic system; };
+in
+
+{
+  testers = prev.testers or { } // {
+    legacyDistros = {
+      inherit debian ubuntu fedora;
+    };
+  };
+}

tests/debian.nix

@@ -1,6 +1,6 @@
 { pkgs, package, system }:
 let
-  lib = package.${system};
+  lib = package;
   multiUserTest = runner: (runner {
     sharedDirs = {};
     testScript = ''
@@ -49,4 +49,4 @@ in {
   }).sandboxed;
 } //
 runTestOnEveryImage multiUserTest //
-package.${system}.debian.images
+package.debian.images

tests/fedora.nix

@@ -1,6 +1,6 @@
 { pkgs, package, system }:
 let
-  lib = package.${system};
+  lib = package;
   multiUserTest = runner: (runner {
     sharedDirs = {};
     testScript = ''
@@ -49,4 +49,4 @@ in {
   }).sandboxed;
 } //
 runTestOnEveryImage multiUserTest //
-package.${system}.fedora.images
+package.fedora.images

tests/ubuntu.nix

@@ -1,7 +1,7 @@
 { pkgs, package, system }:
 
 let
-  lib = package.${system};
+  lib = package;
   multiUserTest = runner: (runner {
     sharedDirs = {};
     testScript = ''
@@ -50,5 +50,5 @@ in {
   }).sandboxed;
 
 }
-// package.${system}.ubuntu.images
+// package.ubuntu.images
 // runTestOnEveryImage multiUserTest