The only test that really needs to be done outdoors on a bright day is the CYA test, which does not need to be done too often (a few times per season typically), so unless you are a vampire this should not be too much of an issue. (No offensive meant to vampires, or as they may prefer to be called people with light sensitivity and alternative dietary requirements). For the rest of the tests do them indoors under good lighting, for the color matching test like pH hold them up to a good white background, a white wall, white appliance door, etc.
Ike