test(datamigrate): migrate controller tests to Ginkgo v2 (#5710)

* test(datamigrate): migrate controller tests to Ginkgo v2

Signed-off-by: Harsh <harshmastic@gmail.com>

* test(datamigrate): address Copilot review findings

- Fix misleading comment on running-job test (returns DeepCopy, not nil)
- Rename NodeAffinity test to reflect actual assertion scope
- Improve suspend test: start STS at 0 replicas for observable scaling,
  assert job.Spec.Suspend is flipped to false

Signed-off-by: Harsh <harshmastic@gmail.com>

* test(datamigrate): deduplicate repeated test literals

Signed-off-by: Harsh <harshmastic@gmail.com>

---------

Signed-off-by: Harsh <harshmastic@gmail.com>

Author: hxrshxz

pkg/controllers/v1alpha1/datamigrate/datamigrate_controller_test.go

@@ -0,0 +1,94 @@
+/*
+Copyright 2026 The Fluid Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package datamigrate
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/tools/record"
+
+	datav1alpha1 "github.com/fluid-cloudnative/fluid/api/v1alpha1"
+	"github.com/fluid-cloudnative/fluid/pkg/utils/fake"
+)
+
+var _ = Describe("DataMigrateReconciler", func() {
+	Describe("NewDataMigrateReconciler", func() {
+		It("should create a reconciler with the provided fields", func() {
+			scheme := runtime.NewScheme()
+			fakeClient := fake.NewFakeClientWithScheme(scheme)
+			log := fake.NullLogger()
+			recorder := record.NewFakeRecorder(10)
+
+			r := NewDataMigrateReconciler(fakeClient, log, scheme, recorder)
+
+			Expect(r).NotTo(BeNil())
+			Expect(r.Scheme).To(Equal(scheme))
+			Expect(r.OperationReconciler).NotTo(BeNil())
+		})
+	})
+
+	Describe("ControllerName", func() {
+		It("should return DataMigrateReconciler", func() {
+			scheme := runtime.NewScheme()
+			fakeClient := fake.NewFakeClientWithScheme(scheme)
+			log := fake.NullLogger()
+			recorder := record.NewFakeRecorder(10)
+
+			r := NewDataMigrateReconciler(fakeClient, log, scheme, recorder)
+
+			Expect(r.ControllerName()).To(Equal("DataMigrateReconciler"))
+		})
+	})
+
+	Describe("Build", func() {
+		It("should return a dataMigrateOperation when given a DataMigrate object", func() {
+			scheme := runtime.NewScheme()
+			fakeClient := fake.NewFakeClientWithScheme(scheme)
+			log := fake.NullLogger()
+			recorder := record.NewFakeRecorder(10)
+
+			r := NewDataMigrateReconciler(fakeClient, log, scheme, recorder)
+
+			dm := &datav1alpha1.DataMigrate{}
+			dm.Name = "test-migrate"
+			dm.Namespace = "default"
+
+			op, err := r.Build(dm)
+
+			Expect(err).NotTo(HaveOccurred())
+			Expect(op).NotTo(BeNil())
+		})
+
+		It("should return an error when given a non-DataMigrate object", func() {
+			scheme := runtime.NewScheme()
+			fakeClient := fake.NewFakeClientWithScheme(scheme)
+			log := fake.NullLogger()
+			recorder := record.NewFakeRecorder(10)
+
+			r := NewDataMigrateReconciler(fakeClient, log, scheme, recorder)
+
+			notDM := &datav1alpha1.DataLoad{}
+
+			op, err := r.Build(notDM)
+
+			Expect(err).To(HaveOccurred())
+			Expect(op).To(BeNil())
+		})
+	})
+})