Improve error message for `player_id` contains NA

[Stéphane Caron]

I did noticed that we passing a vector of player_id containing at least one NA, we received this error :

Error in tidy_players_meta(players_id = unique(dt_draft$player_id), keep_id = TRUE) :
argument 'players_id' should be a vector of integers

Maybe would be helpful to receive a more descriptive error message.

[J.P. Le Cavalier]

I made a comprehensive review of argument assertions following your advice. It's now implemented with 1256bb5. Feel free to re-install de master branch and test.

You can appreciate the new behaviour below:

tidy_players_meta(c(1, 8476981, NA))
##       player_name player_active player_roster_status player_number player_position player_position_type player_nationality player_birth_country player_birth_stateprovince player_birth_city player_birth_date
##  1: Josh Anderson          TRUE                    Y            17               R                    F                CAN                  CAN                         ON        Burlington        1994-05-07
##     player_dead player_death_date player_inches player_pounds player_hand player_rookie player_hof player_hof_year player_nhl_100 team_abbreviation
##  1:       FALSE              <NA>            75           226           R         FALSE      FALSE              NA          FALSE               MTL
##  Warning messages:
##  1: In assert_players_id(players_id) :
##    NAs were detected and dropped in the 'players_id' argument
##  2: In assert_players_id(players_id) :
##    the following elements of the argument 'players_id' were dropped since not identified as valid NHL player IDs: 1

I will close the issue, please reopen if there is anything else related to assertions that could still be improve.