Whenever someone test fires missiles they are testing to ensure the missiles are working properly. The only need for these to work properly is in case of war or a time of national defense. This is Russia's way of flexing their military muscle and threatening Ukraine into doing what they want them to do.
Overall I think Russia wants to flex their military muscles at Ukraine and show them that Russia will impose it's will when it feels like it, I think Russia is aggressively maneuvering in Ukraine and the entire situation is very unstable and anything can happen in the next few days.
At the very least, Russia's test firing of missiles was saber rattling and fits in with the strategy of Putin, as he and the Russian parliament have occupied the Crimea and also sent a warship to Cuba. It is the same thing that North Korea does every time they want to flex their muscles.
The test fire of missiles by Russia is a planned routine test. We should not be drawing connections and lines where there are none. Russia is protecting their interests in Ukraine, particularly the ports they have been renting and want to make sure they still have access to. The missile tests were planned and scheduled far before the uprising in Ukraine came to a boiling point.