feat: initial testing support

test/default.nix

@@ -0,0 +1,28 @@
+{ pkgs ? import <nixpkgs> {}
+, kubenix ? import ../. {inherit pkgs;}
+, lib ? kubenix.lib
+
+# whether any testing error should throw an error
+, throwError ? true }:
+
+with lib;
+
+(evalModules {
+  modules = [
+    ./modules/testing.nix
+
+    {
+      testing.throwError = throwError;
+      testing.tests = [
+        ./k8s/simple.nix
+        ./k8s/deployment.nix
+      ];
+    }
+  ];
+  args = {
+    inherit pkgs;
+  };
+  specialArgs = {
+    inherit kubenix;
+  };
+}).config.testing.result