test: add CRD roundtrip fuzz tests

Taskfile.yml

@@ -132,6 +132,13 @@ tasks:
   build:
     cmds:
       - go build -o bin/manager main.go
+  fuzz:
+    desc: "Run fuzz tests with a configurable duration (default 30s per target)"
+    vars:
+      FUZZTIME: '{{.FUZZTIME | default "30s"}}'
+    cmds:
+      - go test ./api/v1alpha1/ -run=^$ -fuzz=FuzzPlatformMeshRoundTrip -fuzztime={{.FUZZTIME}} -count=1
+
   docker-build:
     cmds:
       - docker build .

api/v1alpha1/roundtrip_fuzz_test.go

@@ -0,0 +1,90 @@
+package v1alpha1
+
+import (
+	"encoding/json"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/equality"
+)
+
+func FuzzPlatformMeshRoundTrip(f *testing.F) {
+	f.Add([]byte(`{
+		"spec": {
+			"exposure": {
+				"baseDomain": "example.com",
+				"port": 443,
+				"protocol": "https"
+			},
+			"kcp": {
+				"providerConnections": [{
+					"path": "root:orgs:default",
+					"secret": "provider-kubeconfig",
+					"external": false
+				}],
+				"extraWorkspaces": [{
+					"path": "root:orgs:extra",
+					"type": {"name": "universal", "path": "root"}
+				}]
+			},
+			"ocm": {
+				"repo": {"name": "platform-mesh"},
+				"component": {"name": "platform-mesh"},
+				"referencePath": [{"name": "ref1"}]
+			},
+			"featureToggles": [{"name": "feature-a", "parameters": {"key": "val"}}]
+		}
+	}`))
+	f.Add([]byte(`{
+		"spec": {
+			"kcp": {
+				"providerConnections": [{
+					"path": "root:orgs:prod",
+					"secret": "prod-secret",
+					"external": true,
+					"adminAuth": true
+				}],
+				"extraDefaultAPIBindings": [{
+					"workspaceTypePath": "root:types",
+					"export": "my-export",
+					"path": "root:orgs"
+				}]
+			},
+			"wait": {
+				"resourceTypes": [{
+					"name": "my-deploy",
+					"namespace": "default"
+				}]
+			}
+		}
+	}`))
+	f.Add([]byte(`{}`))
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		fuzzRoundTrip(t, data, &PlatformMesh{}, &PlatformMesh{})
+	})
+}
+
+// fuzzRoundTrip unmarshals arbitrary JSON into obj, marshals it back, unmarshals
+// into obj2, and checks semantic equality. We use equality.Semantic.DeepEqual from
+// k8s.io/apimachinery which treats nil and empty slices/maps as equivalent — the
+// standard Kubernetes comparison semantic for API objects.
+func fuzzRoundTrip[T any](t *testing.T, data []byte, obj *T, obj2 *T) {
+	t.Helper()
+
+	if err := json.Unmarshal(data, obj); err != nil {
+		return
+	}
+
+	roundtripped, err := json.Marshal(obj)
+	if err != nil {
+		t.Fatalf("failed to marshal: %v", err)
+	}
+
+	if err := json.Unmarshal(roundtripped, obj2); err != nil {
+		t.Fatalf("failed to unmarshal roundtripped data: %v", err)
+	}
+
+	if !equality.Semantic.DeepEqual(obj, obj2) {
+		t.Errorf("roundtrip mismatch for %T", obj)
+	}
+}