feat(legacy): improve legacy support, add more tests

tests/legacy/k8s.nix

@@ -0,0 +1,57 @@
+{ config, lib, kubenix, pkgs, k8sVersion, ... }:
+
+with lib;
+
+let
+  cfg = config.kubernetes.api.resources.deployments.app;
+in {
+  imports = with kubenix.modules; [ test k8s legacy ];
+
+  test = {
+    name = "legacy-k8s";
+    description = "Simple test kubenix legacy kubernetes support";
+    assertions = [{
+      message = "should have correct resource options set";
+      assertion =
+        cfg.kind == "Deployment" &&
+        cfg.metadata.name == "app";
+    } {
+      message = "should have correct defaults set";
+      assertion =
+        cfg.metadata.namespace == "test" &&
+        cfg.metadata.labels.label1 == "value1" &&
+        cfg.metadata.labels.label2 == "value2";
+    }];
+  };
+
+  kubernetes.version = k8sVersion;
+
+  kubernetes.resources.deployments.app = {
+    spec = {
+      replicas = 2;
+      selector = {
+        matchLabels.app = "app";
+      };
+      template.spec = {
+        containers.app = {
+          image = "hello-world";
+        };
+      };
+    };
+  };
+
+  kubernetes.resources.configMaps.app = {
+    data."my-conf.json" = builtins.toJSON {};
+  };
+
+  kubernetes.defaults = {
+    all = [{
+      metadata.namespace = "test";
+      metadata.labels.label1 = "value1";
+    }];
+
+    deployments = [{
+      metadata.labels.label2 = "value2";
+    }];
+  };
+}