Parallel execution of unittests

[Jacob Carlborg via Digitalmars-d]

On 2014-04-30 22:41, Andrei Alexandrescu wrote:

> Yah I think that's possible but I'd like the name to be part of the
> function name as well e.g. unittest__%s.

Why is that necessary? To have the correct symbol name when debugging?

>> I'm using something quite similar to RSpec from the Ruby world:
>>
>> describe! "toMsec" in {
>>      it! "returns the time in milliseconds" in {
>>          assert(true);
>>      }
>> }
>>
>> This uses the old syntax, with UDA's it becomes something like this:
>>
>> @describe("toMsec")
>> {
>>      @it("returns the time in milliseconds") unittest
>>      {
>>          assert(true);
>>      }
>> }
>
> That looks... interesting.

The Ruby syntax looks like this:

describe "toMsec" do
   it "reruns the time in milliseconds" do
     assert true
   end

   context "when the time parameter is nil" do
     it "returns nil" do
       assert true
     end
   end
end

The interesting part about the Ruby implementation is that each it-block 
(the code between do/end) is executed in the context of an anonymous 
class instance. Each describe/context-block is turned in to a class, 
nested blocks inherit from the outer block. In D the implementation 
would look like this:

class __toMsec
{
     void __someUniqueName123 ()
     {
     }

     class __SomeUniqueName456 : __toMsec
     {
         void __someUniqueName789 ()
         {
         }
     }
}

Each it-block (unit test) will be executed in a new instance of the 
closest surrounding class. This means you can have helper methods and 
instance variables shared across multiple test, but they will each get a 
fresh copy of the data.

Since the describe-blocks are implemented with classes that inherit you 
can override helper methods in subclasses.

The unit test runner can also print out a documentation, basically all 
text in the "it" and "describe" parameters. Something like this: 
https://coderwall-assets-0.s3.amazonaws.com/uploads/picture/file/1949/rspec_html_screen.png

-- 
/Jacob Carlborg