fixed stubbing method

Author: liustve

aws-distro-opentelemetry-node-autoinstrumentation/test/exporter/otlp/aws/common/otlp-aws-base-exporter.test.ts

@@ -161,15 +161,14 @@ export abstract class OTLPAwsBaseExporterTest {
   private testSigningFails(done: () => void) {
     this.sandbox.restore();
     this.sandbox = sinon.createSandbox();
-
     this.sandbox.stub(AwsAuthenticator.prototype, 'authenticate').resolves(undefined);
 
     const exporterClass = this.getExporter();
     const exporter = new exporterClass(this.getEndpoint() + this.getEndpointPath());
 
     exporter.export([], (result: ExportResult) => {
       expect(result.code).toBe(ExportResultCode.FAILED);
-      expect(this.scope.isDone()).toBe(true);
+      expect(this.scope.isDone()).toBe(false);
       done();
     });
   }