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[Erl_Question05]gen_server怎么去写eunit?

Prework:

  怎样写一个基本的Eunit? Doc.

1. 加入头文件:声明此模块以”_test”结尾的函数都是测试用,并在编译时自动在这个模块里加入test()函数(当然这个可以用宏来控制)

-include_lib("eunit/include/eunit.hrl").

2.编写测试用例:”*_test()”函数":

reverse_nil_test() -> [] = lists:reverse([]).
reverse_one_test() -> [1] = lists:reverse([1]).
reverse_two_test() -> [2,1] = lists:reverse([1,2]).
%%也可以用宏:这个有好几种,很方便,要用就看文档,比不用宏的优势在于出错信息详细
length_test() -> ?assert(length([1,2,3]) =:= 3).

3. 运行 Eunit

  编译Module –> 然后:

Module:test().
%%
eunit:test(Module).

以上是一个最简单的Eunit的例子,那么:

Question: 类似gen_server有启动进程类的Eunit怎么写?有并发的怎么写?

基本Code形式:

-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-compile({no_auto_import, [get/1, put/2]}).

basic_test_() ->
    {setup, 
        fun() -> 
            ?debugFmt("Starting ~p", [?MODULE]),
            case start_link() of
                {error, {already_started, _}} ->
                    ok;
                {ok, _} ->
                    do_stop
            end
        end,
        fun(Stop) -> 
            case Stop of 
                do_stop -> stop();
                ok -> ok 
            end
        end,
        [
            {timeout, 60, fun normal_insert/0},
            {timeout, 60, fun ttl_insert/0}
        ]
    }.
noraml_insert() ->
    todo.
ttl_insert() ->
    todo.
-endif.
Eunit提供以下格式:
%%To make the descriptions simpler, we first list some definitions:
Setup     () -> (R::any())
SetupX     (X::any()) -> (R::any())
Cleanup     (R::any()) -> any()
CleanupX     (X::any(), R::any()) -> any()
Instantiator     ((R::any()) -> Tests) | {with, [AbstractTestFun::((any()) -> any())]}
Where     local | spawn | {spawn, Node::atom()}
Table .1:   (these are explained in more detail further below.)

%%The following representations specify fixture handling for test sets:

{setup, Setup, Tests | Instantiator}
{setup, Setup, Cleanup, Tests | Instantiator}
{setup, Where, Setup, Tests | Instantiator}
{setup, Where, Setup, Cleanup, Tests | Instantiator}
Setup     () -> (R::any())
SetupX     (X::any()) -> (R::any())
Cleanup     (R::any()) -> any()
CleanupX     (X::any(), R::any()) -> any()
Instantiator     ((R::any()) -> Tests) | {with, [AbstractTestFun::((any()) -> any())]}
Where     local | spawn | {spawn, Node::atom()}

我们上面就是用的: {setup,Setup,Cleanup,TestList}这种,所以用Setup启动,运行TestList后用启动Setup的返回值传入Cleanup(Val)结束!

Tip: 如果你想用新起进程来测试一个模块【gen_server是不需要这样子的,本来就是新起了个进程】可以参照Where参数。

通过以上,我们就可以写出很漂亮的gen_server的enuit函数啦!!

 

那么如何让多个enuit并行跑呢?比如不相关的几个gen_server并行跑起来!

用参数:inparallel

base_test_() ->
    {setup, spawn, 
        fun() -> start() end,
        fun(_) -> stop() end,
        {inparallel, 3,[
            {timeout, 60, funnormal_insert/0},
            {timeout, 60, ttl_insert/0}
        ]}
    }.

惊喜:可以指定同时跑几个哦,上面指定了3个,不指定也可以的.

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一个好的application一定要有可靠的测试用例!,但是如果你在程序里面大量用有副作用的进程字典,还是很难写enuit的…