How to do a literature review on practical research (thesis)?
In general, the literature review means discussing the ways that other people have tried to solve similar problems in the past, and then giving some comparison/contrast between what has been done previously and what you are about to. i.e. put your work in context of existing work.  You might see it worded something like this:

"Historically, two main strategies have been used by companies to reduce testing time and cost.  Strategy 1 was first described in Article #1 and consists of using trained monkeys to do the testing.  Strategy 2 is discussed in several articles including article #2 and article #3 and involves just assuming everything works fine and going out to lunch early without doing any actual testing.  Strategy 1 works well, but does not scale to large projects due to a shortage of properly trained monkeys, as described in book #4.  Strategy 2 scales very well, but can often miss subtle errors, as mentioned by author #5.  In this thesis, we will present a new strategy, which is more scalable than strategy 1, but does not suffer from the quality problems of strategy 2."

Depending on the length of your thesis, you might go into a lot of detail here.  E.g. for a Ph. D. disseration you might have a couple of pages on strategy #1, a couple of pages on strategy #2, etc.  But for a short article a sentence or two is usually enough.