test header controller
Merge branch 'step-2' into step-3
add test service
refacto test service
refacto test
Merge branch 'step-2' into step-3
add test service
Merge branch 'step-3' into step-4-1
Merge branch 'step-4-1' into step-4-2
test directive
Merge branch 'step-4-2' into step-5
add test popular and search controllers