fix: return 409 error in createJob() for dry run (#1003)

* fix: return 409 error in createJob() dry run

* fix test

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Author: steffnay

src/bigquery.ts

@@ -1518,6 +1518,9 @@ export class BigQuery extends common.Service {
     callback?: JobCallback
   ): void | Promise<JobResponse> {
     const JOB_ID_PROVIDED = typeof options.jobId !== 'undefined';
+    const DRY_RUN = options.configuration?.dryRun
+      ? options.configuration.dryRun
+      : false;
 
     const reqOpts = Object.assign({}, options);
     let jobId = JOB_ID_PROVIDED ? reqOpts.jobId : uuid.v4();
@@ -1558,7 +1561,8 @@ export class BigQuery extends common.Service {
         if (err) {
           if (
             (err as common.ApiError).code === ALREADY_EXISTS_CODE &&
-            !JOB_ID_PROVIDED
+            !JOB_ID_PROVIDED &&
+            !DRY_RUN
           ) {
             // The last insert attempt flaked, but the API still processed the
             // request and created the job. Because of our "autoRetry" feature,

test/bigquery.ts

@@ -1749,6 +1749,20 @@ describe('BigQuery', () => {
       });
     });
 
+    it('should return 409 if dryRun is true', done => {
+      const error = new util.ApiError('Error.');
+      error.code = 409;
+
+      bq.request = (reqOpts: DecorateRequestOptions, callback: Function) => {
+        callback(error);
+      };
+
+      bq.createJob({configuration: {dryRun: true}}, (err: Error) => {
+        assert.strictEqual(err, error);
+        done();
+      });
+    });
+
     it('should return any status errors', done => {
       const errors = [{reason: 'notFound'}];
       const response = extend(true, {}, RESPONSE, {