add DefaultPool lazy load test

Author: purnesh42H

xds/internal/xdsclient/pool_test.go

@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2025 gRPC 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 xdsclient
+
+import (
+"encoding/json"
+"fmt"
+"testing"
+
+"github.com/google/uuid"
+"google.golang.org/grpc/internal/envconfig"
+"google.golang.org/grpc/internal/testutils/stats"
+"google.golang.org/grpc/internal/xds/bootstrap"
+)
+
+// TestDefaultPool_LazyLoadBootstrapConfig verifies that the DefaultPool
+// lazily loads the bootstrap configuration from environment variables when
+// an xDS client is created for the first time.
+func (s) TestDefaultPool_LazyLoadBootstrapConfig(t *testing.T) {
+bs, err := bootstrap.NewContentsForTesting(bootstrap.ConfigOptionsForTesting{
+Servers: []byte(fmt.Sprintf(`[{
+"server_uri": %q,
+"channel_creds": [{"type": "insecure"}]
+}]`, "non-existent-management-server")),
+Node: []byte(fmt.Sprintf(`{"id": "%s"}`, uuid.New().String())),
+CertificateProviders: map[string]json.RawMessage{
+"cert-provider-instance": json.RawMessage("{}"),
+},
+})
+if err != nil {
+t.Fatalf("Failed to create bootstrap configuration: %v", err)
+}
+
+origBootstrapContent := envconfig.XDSBootstrapFileContent
+envconfig.XDSBootstrapFileContent = string(bs)
+defer func() { envconfig.XDSBootstrapFileContent = origBootstrapContent }()
+
+if DefaultPool.BootstrapConfigForTesting() != nil {
+t.Fatalf("DefaultPool.BootstrapConfigForTesting() = %v, want nil", DefaultPool.BootstrapConfigForTesting())
+}
+
+_, closeFunc, err := DefaultPool.NewClient(t.Name(), &stats.NoopMetricsRecorder{})
+if err != nil {
+t.Fatalf("Failed to create xDS client: %v", err)
+}
+defer func() {
+closeFunc()
+DefaultPool.UnsetBootstrapConfigForTesting()
+}()
+
+if DefaultPool.BootstrapConfigForTesting() == nil {
+t.Fatalf("DefaultPool.BootstrapConfigForTesting() = nil, want %v", DefaultPool.BootstrapConfigForTesting())
+}
+}