The reading tests that are timed (1 minute), such as Phoneme Segmenting, Letter Names, Letter Sounds, Word Reading Fluency, and Passage Reading Fluency are meant to glean a quick look at what a student knows. In those reading tests where time is a factor, the goal is to get a snapshot sample of what a student knows such as phonics, letter/word recognition and fluency (can a student fluently read a word or a passage or not).
The multiple-choice reading comprehension and math tests, which can be taken online, are not timed. Because multiple-choice reading comprehension targets the literal, inferential, and evaluative nature of a reading passage, they represent the most challenging aspects of reading because they require some very nuanced reading of the stories. For this reason there is no set time a student is required to complete a test though generally students finish in about 25-30 minutes.