feat(clan/services): init test-suite for eval test

lib/distributed-service/flake-module.nix

@@ -0,0 +1,54 @@
+{ self, inputs, ... }:
+let
+  inputOverrides = builtins.concatStringsSep " " (
+    builtins.map (input: " --override-input ${input} ${inputs.${input}}") (builtins.attrNames inputs)
+  );
+in
+{
+  perSystem =
+    {
+      pkgs,
+      lib,
+      config,
+      system,
+      self',
+      ...
+    }:
+    {
+      devShells.inventory-schema = pkgs.mkShell {
+        inputsFrom = with config.checks; [
+          lib-inventory-eval
+          self'.devShells.default
+        ];
+      };
+
+      legacyPackages.schemas = (
+        import ./schemas {
+          inherit
+            pkgs
+            self
+            lib
+            self'
+            ;
+        }
+      );
+
+      # Run: nix-unit --extra-experimental-features flakes --flake .#legacyPackages.x86_64-linux.<attrName>
+      legacyPackages.evalTest-distributedServices = import ./tests {
+        inherit lib self;
+      };
+
+      checks = {
+        lib-distributedServices-eval = pkgs.runCommand "tests" { nativeBuildInputs = [ pkgs.nix-unit ]; } ''
+          export HOME="$(realpath .)"
+          export NIX_ABORT_ON_WARN=1
+          nix-unit --eval-store "$HOME" \
+            --extra-experimental-features flakes \
+            ${inputOverrides} \
+            --flake ${self}#legacyPackages.${system}.distributedServices
+
+          touch $out
+        '';
+      };
+    };
+}

lib/distributed-service/tests/default.nix

@@ -0,0 +1,61 @@
+{
+  lib,
+  ...
+}:
+let
+  inherit (lib)
+    evalModules
+    mkOption
+    types
+    ;
+
+  inherit (types)
+    submodule
+    attrsOf
+    str
+    ;
+
+  evalInventory =
+    m:
+    (evalModules {
+      # Static modules
+      modules = [
+        ../../inventory/build-inventory/interface.nix
+        {
+          modules.test = {};
+        }
+        m
+      ];
+    }).config;
+
+  flakeFixture = { inputs = {}; };
+
+  callInventoryAdapter = inventoryModule: import ../inventory-adapter.nix { inherit lib; flake = flakeFixture; inventory = evalInventory inventoryModule; };
+in
+{
+  test_simple =
+    let res = callInventoryAdapter {
+      # Authored module
+      # A minimal module looks like this
+      # It isn't exactly doing anything but it's a valid module that produces an output
+      modules."simple-module" = {
+        _class = "clan.service";
+        manifest = {
+          name = "netwitness";
+        };
+      };
+      # User config
+      instances."instance_foo" = {
+        module = {
+          name = "simple-module";
+        };
+      };
+    };
+    in
+  {
+    # Test that the module is mapped into the output
+    # We might change the attribute name in the future
+    expr = res.evals ? "self-simple-module";
+    expected = true;
+  };
+}