Why is Sri Lanka struggling to play test cricket as competitively as they play ODI's ?

obviously the lack of great bowlers,,but still there are ways to win tests with an average bowling attck if they bowl well according to a plan

Sri Lanka cricket board`s main aim is to make money somehow to cover the losses they make bcz of corruption so tests are not their priority..they have become muppets of BCCI and have no vision

if they want they can play more tests (or atleast stop cancelling the remaining ones to play IPL - already caceled 3 tests against SA , and 2 against WI for this year alone!) , work with young bowlers and improve them while they get more experience

Sri Lanka need more test matches

I think all south asian team struggle in Australia and England so the Sirilankans are doing in Australia....

other example is of India 8 straight foreign defeats (in eng and aus).

sounds like a similar problem to India

Because they have been playing a second string Australian OD side..