Function testSigning

test/integration/auth/mongodb_aws.test.ts:247–299

      });

      const testSigning = async creds => {
        const host = 'sts.amazonaws.com';
        const body = 'Action=GetCallerIdentity&Version=2011-06-15';
        const headers: {
          'Content-Type': 'application/x-www-form-urlencoded';
          'Content-Length': number;
          'X-MongoDB-Server-Nonce': string;
          'X-MongoDB-GS2-CB-Flag': 'n';
        } = {
          'Content-Type': 'application/x-www-form-urlencoded',
          'Content-Length': body.length,
          'X-MongoDB-Server-Nonce': 'fakenonce',
          'X-MongoDB-GS2-CB-Flag': 'n'
        };
        const signedHeaders = await aws4Sign(
          {
            method: 'POST',
            host,
            path: '/',
            region: 'us-east-1',
            service: 'sts',
            headers: headers,
            body,
            date: new Date()
          },
          creds
        );

        const authorization = signedHeaders.Authorization;
        const xAmzDate = signedHeaders['X-Amz-Date'];

        const fetchHeaders = new Headers();
        for (const [key, value] of Object.entries(headers)) {
          fetchHeaders.append(key, value.toString());
        }
        if (credentials && credentials.sessionToken) {
          fetchHeaders.append('X-Amz-Security-Token', credentials.sessionToken);
        }
        fetchHeaders.append('Authorization', authorization);
        fetchHeaders.append('X-Amz-Date', xAmzDate);
        const response = await fetch('https://sts.amazonaws.com', {
          method: 'POST',
          headers: fetchHeaders,
          body
        });
        const text = await response.text();

        expect(response.status).to.equal(200);
        expect(response.statusText).to.equal('OK');
        expect(text).to.match(
          /<GetCallerIdentityResponse xmlns="https:\/\/sts.amazonaws.com\/doc\/2011-06-15\/">/
        );
      };

      describe('when using premanent credentials', function () {
        beforeEach(async function () {