[erlang-questions] Structuring an Eunit Suite

[Adam Lindberg]

Hi Ben,

Let's see if I understood you correctly...

The example in the EUnit documentation:

fib_test_() ->
       [?_assert(fib(0) == 1),
        ?_assert(fib(1) == 1),
        ?_assert(fib(2) == 2),
        ?_assert(fib(3) == 3),
        ?_assert(fib(4) == 5),
        ?_assert(fib(5) == 8),
        ?_assertException(error, function_clause, fib(-1)),
        ?_assert(fib(31) == 2178309)
       ].

Could be written as (without the exception assert):

fib_test_() ->
    lists:map(fun assert_fib/1, [{0,1}, {1,1}, {2,2}, {3,3}, {4,5}, {5,8}, {31,2178309}]).

assert_fib({Value, Expected) ->
    ?_assert(fib(Value) == Expected).

If foo_test(Connection) returns a test fun, e.g. ?_assert(...) or similar, and you want to run this test for many different types of connections you could generate a list of such tests:

foo_test_() -> % Note the trailing underscore
    [test_util:foo_test(new_connection()), test_util:foo_test(some_other_connection())].

Note that the function name ends in underscore. This means that the function is not a test itself, it returns a test (which will be executed at a later time). Even nicer could be like this:

foo_test_() ->
    lists:map(fun test_util:foo_test/1, [new_connection(), some_other_connection()]).

Does this seem to be what you want?

Cheers,
Adam

----- "Ben Hood" <0x6e6562@REDACTED> wrote:

> Hi,
> 
> I'm currently using Eunit in a very agricultural fashion and would
> like to use more of the Eunit infrastructure to make the tests less
> verbose.
> 
> I have a suite of tests that each connect to a message server and
> execute a number of commands.
> 
> I want to be able to parameterize where the connection supplied from,
> so that I can re-use the tests on different transports.
> 
> What I've got now is a suite that looks like this:
> 
> foo_test() ->
>      test_util:foo_test(new_connection()).
> ......
> 
> new_connection() ->
>      %% returns a specific connection to the server
> 
> ......
> 
> and all of the real tests are in the test_util module, e.g:
> 
> foo_test(Connection) ->
>      %% assert something
> 
> Ideally I would like eunit to do something like
> 
> "foreach _test function in the test_util module, create a new
> connection and pass it as a function argument"
> 
> Is this possible?
> 
> Thanks for any suggestions,
> 
> Ben
> 
> PS The link the source is here:
> 
> http://hg.rabbitmq.com/rabbitmq-erlang-client/file/437d0e4d66c8/src/network_client_test.erl
> http://hg.rabbitmq.com/rabbitmq-erlang-client/file/437d0e4d66c8/src/test_util.erl
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