Add plan preview tests for kubernetes_multicluster plugin

Add plugin_test.go and testdata covering single-target and multi-target scenarios.

Signed-off-by: Mohammed Firdous <124298708+mohammedfirdouss@users.noreply.github.com>

Author: mohammedfirdouss

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/plugin_test.go

@@ -0,0 +1,230 @@
+// Copyright 2025 The PipeCD 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 planpreview
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	sdk "github.com/pipe-cd/piped-plugin-sdk-go"
+	"github.com/pipe-cd/piped-plugin-sdk-go/logpersister/logpersistertest"
+	"github.com/pipe-cd/piped-plugin-sdk-go/toolregistry/toolregistrytest"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap/zaptest"
+
+	kubeconfig "github.com/pipe-cd/pipecd/pkg/app/pipedv1/plugin/kubernetes_multicluster/config"
+)
+
+const (
+	pluginName    = "kubernetes_multicluster"
+	runningCommit = "abc000"
+	targetCommit  = "abc123"
+)
+
+func makeDeployTargets(names ...string) []*sdk.DeployTarget[kubeconfig.KubernetesDeployTargetConfig] {
+	dts := make([]*sdk.DeployTarget[kubeconfig.KubernetesDeployTargetConfig], 0, len(names))
+	for _, name := range names {
+		dts = append(dts, &sdk.DeployTarget[kubeconfig.KubernetesDeployTargetConfig]{Name: name})
+	}
+	return dts
+}
+
+func makeInput(
+	t *testing.T,
+	appConfigFile string,
+	targetAppDir string,
+	runningAppDir string,
+) *sdk.GetPlanPreviewInput[kubeconfig.KubernetesApplicationSpec] {
+	t.Helper()
+
+	appCfg := sdk.LoadApplicationConfigForTest[kubeconfig.KubernetesApplicationSpec](t, appConfigFile, pluginName)
+	testRegistry := toolregistrytest.NewTestToolRegistry(t)
+
+	targetDS := sdk.DeploymentSource[kubeconfig.KubernetesApplicationSpec]{
+		ApplicationDirectory:      targetAppDir,
+		CommitHash:                targetCommit,
+		ApplicationConfig:         appCfg,
+		ApplicationConfigFilename: "app.pipecd.yaml",
+	}
+
+	input := &sdk.GetPlanPreviewInput[kubeconfig.KubernetesApplicationSpec]{
+		Request: sdk.GetPlanPreviewRequest[kubeconfig.KubernetesApplicationSpec]{
+			ApplicationID:          "app-id",
+			ApplicationName:        "simple",
+			TargetDeploymentSource: targetDS,
+		},
+		Client: sdk.NewClient(nil, pluginName, "app-id", "", logpersistertest.NewTestLogPersister(t), testRegistry),
+		Logger: zaptest.NewLogger(t),
+	}
+
+	if runningAppDir != "" {
+		input.Request.RunningDeploymentSource = sdk.DeploymentSource[kubeconfig.KubernetesApplicationSpec]{
+			ApplicationDirectory:      runningAppDir,
+			CommitHash:                runningCommit,
+			ApplicationConfig:         appCfg,
+			ApplicationConfigFilename: "app.pipecd.yaml",
+		}
+	}
+
+	return input
+}
+
+func TestPlugin_GetPlanPreview_SingleTarget(t *testing.T) {
+	t.Parallel()
+
+	appCfgFile := filepath.Join("testdata", "single", "app.pipecd.yaml")
+	runningDir := filepath.Join("testdata", "single", "running")
+	targetDir := filepath.Join("testdata", "single", "target")
+	p := &Plugin{}
+
+	tests := []struct {
+		name          string
+		targetDir     string
+		runningDir    string
+		wantNoChange  bool
+		wantSummary   string
+		wantInDetails []string
+	}{
+		{
+			name:         "first deployment (no running source)",
+			targetDir:    targetDir,
+			runningDir:   "",
+			wantNoChange: false,
+			wantSummary:  "1 added manifests, 0 changed manifests, 0 deleted manifests",
+			wantInDetails: []string{
+				"simple",
+				"Deployment",
+			},
+		},
+		{
+			name:         "no change (same files)",
+			targetDir:    runningDir,
+			runningDir:   runningDir,
+			wantNoChange: true,
+			wantSummary:  "No changes were detected",
+		},
+		{
+			name:         "image tag changed",
+			targetDir:    targetDir,
+			runningDir:   runningDir,
+			wantNoChange: false,
+			wantSummary:  "0 added manifests, 1 changed manifests, 0 deleted manifests",
+			wantInDetails: []string{
+				"v0.1.0",
+				"v0.2.0",
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			input := makeInput(t, appCfgFile, tc.targetDir, tc.runningDir)
+
+			resp, err := p.GetPlanPreview(context.Background(), nil, makeDeployTargets("default"), input)
+			require.NoError(t, err)
+			require.Len(t, resp.Results, 1)
+
+			result := resp.Results[0]
+			assert.Equal(t, tc.wantNoChange, result.NoChange)
+			assert.Equal(t, tc.wantSummary, result.Summary)
+			assert.Equal(t, "diff", result.DiffLanguage)
+
+			for _, s := range tc.wantInDetails {
+				assert.Contains(t, string(result.Details), s)
+			}
+			if tc.wantNoChange {
+				assert.Nil(t, result.Details)
+			}
+		})
+	}
+}
+
+func TestPlugin_GetPlanPreview_MultiTarget(t *testing.T) {
+	t.Parallel()
+
+	appCfgFile := filepath.Join("testdata", "multi", "app.pipecd.yaml")
+	runningDir := filepath.Join("testdata", "multi", "running")
+	targetDir := filepath.Join("testdata", "multi", "target")
+	p := &Plugin{}
+	dts := makeDeployTargets("cluster1", "cluster2")
+
+	tests := []struct {
+		name   string
+		checks []struct {
+			deployTarget  string
+			wantNoChange  bool
+			wantSummary   string
+			wantInDetails []string
+		}
+	}{
+		{
+			name: "cluster1 changed, cluster2 unchanged",
+			checks: []struct {
+				deployTarget  string
+				wantNoChange  bool
+				wantSummary   string
+				wantInDetails []string
+			}{
+				{
+					deployTarget:  "cluster1",
+					wantNoChange:  false,
+					wantSummary:   "0 added manifests, 1 changed manifests, 0 deleted manifests",
+					wantInDetails: []string{"v0.1.0", "v0.2.0"},
+				},
+				{
+					deployTarget: "cluster2",
+					wantNoChange: true,
+					wantSummary:  "No changes were detected",
+				},
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			input := makeInput(t, appCfgFile, targetDir, runningDir)
+
+			resp, err := p.GetPlanPreview(context.Background(), nil, dts, input)
+			require.NoError(t, err)
+			require.Len(t, resp.Results, 2)
+
+			for _, check := range tc.checks {
+				var result *sdk.PlanPreviewResult
+				for i := range resp.Results {
+					if resp.Results[i].DeployTarget == check.deployTarget {
+						result = &resp.Results[i]
+						break
+					}
+				}
+				require.NotNil(t, result, "result for deploy target %q not found", check.deployTarget)
+
+				assert.Equal(t, check.wantNoChange, result.NoChange)
+				assert.Equal(t, check.wantSummary, result.Summary)
+				assert.Equal(t, "diff", result.DiffLanguage)
+
+				for _, s := range check.wantInDetails {
+					assert.Contains(t, string(result.Details), s)
+				}
+				if check.wantNoChange {
+					assert.Nil(t, result.Details)
+				}
+			}
+		})
+	}
+}

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/multi/app.pipecd.yaml

@@ -0,0 +1,16 @@
+apiVersion: pipecd.dev/v1beta1
+kind: KubernetesApp
+spec:
+  name: simple
+  plugins:
+    kubernetes_multicluster:
+      input:
+        multiTargets:
+          - target:
+              name: cluster1
+            manifests:
+              - cluster1/deployment.yaml
+          - target:
+              name: cluster2
+            manifests:
+              - cluster2/deployment.yaml

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/multi/running/cluster1/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: simple-cluster1
+  labels:
+    app: simple-cluster1
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: simple-cluster1
+  template:
+    metadata:
+      labels:
+        app: simple-cluster1
+    spec:
+      containers:
+      - name: helloworld
+        image: ghcr.io/pipe-cd/helloworld:v0.1.0
+        ports:
+        - containerPort: 9085

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/multi/running/cluster2/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: simple-cluster2
+  labels:
+    app: simple-cluster2
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: simple-cluster2
+  template:
+    metadata:
+      labels:
+        app: simple-cluster2
+    spec:
+      containers:
+      - name: helloworld
+        image: ghcr.io/pipe-cd/helloworld:v0.1.0
+        ports:
+        - containerPort: 9085

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/multi/target/cluster1/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: simple-cluster1
+  labels:
+    app: simple-cluster1
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: simple-cluster1
+  template:
+    metadata:
+      labels:
+        app: simple-cluster1
+    spec:
+      containers:
+      - name: helloworld
+        image: ghcr.io/pipe-cd/helloworld:v0.2.0
+        ports:
+        - containerPort: 9085

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/multi/target/cluster2/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: simple-cluster2
+  labels:
+    app: simple-cluster2
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: simple-cluster2
+  template:
+    metadata:
+      labels:
+        app: simple-cluster2
+    spec:
+      containers:
+      - name: helloworld
+        image: ghcr.io/pipe-cd/helloworld:v0.1.0
+        ports:
+        - containerPort: 9085

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/single/app.pipecd.yaml

@@ -0,0 +1,9 @@
+apiVersion: pipecd.dev/v1beta1
+kind: KubernetesApp
+spec:
+  name: simple
+  plugins:
+    kubernetes_multicluster:
+      input:
+        manifests:
+          - deployment.yaml

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/single/running/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: simple
+  labels:
+    app: simple
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: simple
+  template:
+    metadata:
+      labels:
+        app: simple
+    spec:
+      containers:
+      - name: helloworld
+        image: ghcr.io/pipe-cd/helloworld:v0.1.0
+        ports:
+        - containerPort: 9085

pkg/app/pipedv1/plugin/kubernetes_multicluster/planpreview/testdata/single/target/deployment.yaml

@@ -0,0 +1,21 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: simple
+  labels:
+    app: simple
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: simple
+  template:
+    metadata:
+      labels:
+        app: simple
+    spec:
+      containers:
+      - name: helloworld
+        image: ghcr.io/pipe-cd/helloworld:v0.2.0
+        ports:
+        - containerPort: 9085