What is the test for determining whether or not the police intended to and did arrest a passenger in a taxi?

It was in the case of Rios v. United States, 364 U.S. 253, 80 S.Ct. 1431, 4 L.Ed.2d 1688, that the court first passed squarely upon the question presented by the instant case. The court there held that it was a question of fact whether or not the police had intended to and did arrest the petitioner when they took their positions at the doors of the taxicab in which he was a passenger. The government had argued that the policemen approached the taxi 'only for the purpose of routine interrogation, and that they had no intent to detain the petitioner beyond the momentary requirements of such a mission.' (P. 262, 80 S.Ct. p. 1436.) The court held that if the trier of the facts so found, then the conduct of the petitioner that thereafter followed amply justified his later arrest, search and subsequent conviction. The facts in Rios are stated as follows at pages 255--256, 80 S.Ct. at page 1433: