OPAG unit tests

[timriffe]

• [x] check for success in a few different input scenarios
• [x] check sums match between input and output
• [x] check output of proper length
• [x] check for console output when informative warnings should be generated
• [x] expect error if OAnew > max(Age_nLx)
• [x] expect errors in other reasonable situations
• [x] canonical test: if the census is actually a stationary population, identical to nLx itself, then we hope to return something proportional to it.
• [x] canonical test: if input census is an exact stable pop (use auxiliary function OPAG_nLx_warp_r)

[tbernardesfaria]

Hi Tim, maybe you can assign this issue for me.