feat: initial testing support

test/modules/testing.nix

@@ -0,0 +1,101 @@
+{ config, pkgs, lib, kubenix, ... }:
+
+with lib;
+
+let
+  cfg = config.testing;
+in {
+  options = {
+    testing.throwError = mkOption {
+      description = "Whether to throw error";
+      type = types.bool;
+      default = true;
+    };
+
+    testing.tests = mkOption {
+      description = "Attribute set of test cases";
+      default = [];
+      type = types.listOf (types.coercedTo types.path (module: {inherit module;}) (types.submodule ({config, ...}: let
+        modules = [config.module ./test.nix {
+          config._module.args.test = config;
+        }];
+
+        test = (kubenix.evalKubernetesModules {
+          check = false;
+          inherit modules;
+        }).config.test;
+
+        evaled = builtins.trace "testing ${test.name}" (kubenix.evalKubernetesModules {
+          inherit modules;
+        });
+      in {
+        options = {
+          module = mkOption {
+            description = "Module defining submodule";
+            type = types.unspecified;
+          };
+
+          name = mkOption {
+            description = "test name";
+            type = types.str;
+            internal = true;
+          };
+
+          description = mkOption {
+            description = "test description";
+            type = types.str;
+            internal = true;
+          };
+
+          evaled = mkOption {
+            description = "Wheter test was evaled";
+            type = types.bool;
+            default =
+              if cfg.throwError
+              then if evaled.config.test.assertions != [] then true else true
+              else (builtins.tryEval evaled.config.test.assertions).success;
+            internal = true;
+          };
+
+          success = mkOption {
+            description = "Whether test was success";
+            type = types.bool;
+            internal = true;
+            default = false;
+          };
+
+          assertions = mkOption {
+            description = "Test result";
+            type = types.unspecified;
+            internal = true;
+            default = [];
+          };
+        };
+
+        config = {
+          inherit (test) name description;
+          assertions = mkIf config.evaled evaled.config.test.assertions;
+          success = mkIf config.evaled (all (el: el.assertion) config.assertions);
+        };
+      })));
+    };
+
+    testing.success = mkOption {
+      description = "Whether testing was a success";
+      type = types.bool;
+      default = all (test: test.success) cfg.tests;
+    };
+
+    testing.result = mkOption {
+      description = "Testing result";
+      type = types.package;
+      default = pkgs.writeText "testing-report.json" (builtins.toJSON {
+        success = cfg.success;
+        tests = map (test: {
+          inherit (test) name description evaled success;
+          assertions = moduleToAttrs test.assertions;
+        }) cfg.tests;
+      });
+    };
+  };
+}