I don't rely too much on certifications to gauge people's fitness to hire. Here's what I'd look for if I were hiring for entry-level positions:
1. Knowledge of the language
2. Knowledge of unit testing frameworks like JUnit 3. Problem solving approach
5. Eagerness to learn
This is in order of increasing importance to me, so #5 is most important. Caveat: although I list "Knowledge of the language" as the least important of the five, you at least need a basic mastery of the language so studying for certification exam can still be helpful and passing the exam can still help you get in the door for a more detailed interview.
Regarding coding tests, you need to practice writing actual programs so you can get over your nerves. The more you practice, the more you'll build up confidence in your ability to meet coding challenges that may be thrown at you.
Campbell Ritchie wrote:How far would you go looking for understanding of general programming principles?
Assuming the question is directed at me, not very deep. I don't even expect many experienced people (5-10 years) to know much about principles--I just don't see that many people who know about them that much any more, unfortunately. Anyone who can explain SOLID, GRASP, DRY, YAGNI and the like reasonably well is probably going to have a good chance at being shortlisted though.
If you have (personal / open source) projects in GitHub, that might also help in your application.
Some Employers like to know if applicants are passionate enough about software development that they continue to code even outside of the work environment.
Now I am super curious what sports would be like if we allowed drugs and tiny ads.