fix: preserve default values in x-goog-request-params header (#251)

- [ ] Regenerate this pull request now.

PiperOrigin-RevId: 474338479

Source-Link: googleapis/googleapis@d5d35e0

Source-Link: googleapis/googleapis-gen@efcd3f9
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiZWZjZDNmOTM5NjJhMTAzZjY4ZjAwM2UyYTFlZWNkZTZmYTIxNmEyNyJ9

packages/google-cloud-mediatranslation/test/gapic_speech_translation_service_v1beta1.ts

@@ -27,6 +27,21 @@ import {PassThrough} from 'stream';
 
 import {protobuf} from 'google-gax';
 
+// Dynamically loaded proto JSON is needed to get the type information
+// to fill in default values for request objects
+const root = protobuf.Root.fromJSON(
+  require('../protos/protos.json')
+).resolveAll();
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+function getTypeDefaultValue(typeName: string, fields: string[]) {
+  let type = root.lookupType(typeName) as protobuf.Type;
+  for (const field of fields.slice(0, -1)) {
+    type = type.fields[field]?.resolvedType as protobuf.Type;
+  }
+  return type.fields[fields[fields.length - 1]]?.defaultValue;
+}
+
 function generateSampleMessage<T extends object>(instance: T) {
   const filledObject = (
     instance.constructor as typeof protobuf.Message
@@ -186,6 +201,7 @@ describe('v1beta1.SpeechTranslationServiceClient', () => {
       const request = generateSampleMessage(
         new protos.google.cloud.mediatranslation.v1beta1.StreamingTranslateSpeechRequest()
       );
+
       const expectedResponse = generateSampleMessage(
         new protos.google.cloud.mediatranslation.v1beta1.StreamingTranslateSpeechResponse()
       );