fix: throw err when fail to get service name list (#230)

* Throw err when fail to get service name list

* Address the comments: update error message; unit test for New API constructor

typescript/src/cli.ts

@@ -32,4 +32,5 @@ async function main() {
 
 main().catch(err => {
   console.error(err);
+  process.exit(1);
 });

typescript/src/schema/api.ts

@@ -93,6 +93,11 @@ export class API {
         this.port = port ?? this.port ?? '443';
         serviceNamesList.push(service.name || this.naming.name);
       });
+    if (serviceNamesList.length === 0) {
+      throw new Error(
+        `Can't find ${this.naming.name}'s service names, please make sure that services are defined in the proto file.`
+      );
+    }
     this.mainServiceName = options.mainServiceName || serviceNamesList[0];
   }
 

typescript/test/unit/api.ts

@@ -23,6 +23,10 @@ describe('schema/api.ts', () => {
     fd.name = 'google/cloud/test/v1/test.proto';
     fd.package = 'google.cloud.test.v1';
     fd.service = [new plugin.google.protobuf.ServiceDescriptorProto()];
+    fd.service[0].name = 'ZService';
+    fd.service[0].options = {
+      '.google.api.defaultHost': 'hostname.example.com:443',
+    };
     const api = new API([fd], 'google.cloud.test.v1', {
       grpcServiceConfig: new plugin.grpc.service_config.ServiceConfig(),
     });
@@ -36,6 +40,10 @@ describe('schema/api.ts', () => {
     fd1.name = 'google/cloud/test/v1/test.proto';
     fd1.package = 'google.cloud.test.v1';
     fd1.service = [new plugin.google.protobuf.ServiceDescriptorProto()];
+    fd1.service[0].name = 'ZService';
+    fd1.service[0].options = {
+      '.google.api.defaultHost': 'hostname.example.com:443',
+    };
     const fd2 = new plugin.google.protobuf.FileDescriptorProto();
     fd2.name = 'google/longrunning/operation.proto';
     fd2.package = 'google.longrunning';
@@ -132,4 +140,16 @@ describe('schema/api.ts', () => {
       '../../protos/google/cloud/example/v1/test.proto',
     ]);
   });
+
+  it('should throw error when the service name is not found', () => {
+    const fd = new plugin.google.protobuf.FileDescriptorProto();
+    fd.name = 'google/cloud/test/v1/test.proto';
+    fd.package = 'google.cloud.test.v1';
+    fd.service = [new plugin.google.protobuf.ServiceDescriptorProto()];
+    assert.throws(() => {
+      const api = new API([fd], 'google.cloud.test.v1', {
+        grpcServiceConfig: new plugin.grpc.service_config.ServiceConfig(),
+      });
+    });
+  });
 });