Is it possible to test all 40 strains of hpv? Please explain.

Yes. But not commercially, only in research or university laboratories do you have anyone interested in doing all 40 strains.
Not realistic. There are in excess of 100 strains. Only research labs that study HPV would have the capability of such testing & each strain or group of strains would require a separate set up & sample.Since less than a dozen strains are associated with human cancer or genital warts, expending resources on the others is not worth the effort. Knowing the strain number might be interesting but not a necessity.