[U-Boot] [PATCH v3 7/8] x86: efi: Add a hello world test program

[Alexander Graf]

On 07/11/2016 10:46, Simon Glass wrote:
> Hi Alex,
>
> On 19 October 2016 at 01:09, Alexander Graf <agraf at suse.de> wrote:
>>
>>
>> On 18/10/2016 22:37, Simon Glass wrote:
>>> Hi Alex,
>>>
>>> On 18 October 2016 at 01:14, Alexander Graf <agraf at suse.de> wrote:
>>>> On 10/18/2016 04:29 AM, Simon Glass wrote:
>>>>>
>>>>> It is useful to have a basic sanity check for EFI loader support. Add a
>>>>> 'bootefi hello' command which loads HelloWord.efi and runs it under
>>>>> U-Boot.
>>>>>
>>>>> Signed-off-by: Simon Glass <sjg at chromium.org>
>>>>> ---
>>>>>
>>>>> Changes in v3:
>>>>> - Include a link to the program instead of adding it to the tree
>>>>
>>>>
>>>> So, uh, where is the link?
>>>
>>> I put it in the README (see the arm patch).
>>>
>>>>
>>>> I'm really not convinced this command buys us anything yet. I do agree that
>>>> we want automated testing - but can't we get that using QEMU and a
>>>> downloadable image file that we pass in as disk and have the distro boot do
>>>> its magic?
>>>
>>> That seems very heavyweight as a sanity check, although I agree it is useful.
>>
>> It's not really much more heavy weight. The "image file" could simply
>> contain your hello world binary. But with this we don't just verify
>> whether "bootefi" works, but also whether the default boot path works ok.
>
> I don't think I understand what you mean by 'image file'. Is it
> something other than the .efi file? Do you mean a disk image?

Yes. For reasonable test coverage, we should also verify that the distro 
defaults wrote a sane boot script that automatically searches for a 
default EFI binary in /efi/boot/bootx86.efi on the first partition of 
all devices and runs it.

So if we just provide an SD card image or hard disk image to QEMU which 
contains a hello world .efi binary as that default boot file, we don't 
only test whether the "bootefi" command works, but also whether the 
distro boot script works.

>
>>
>>> Here I am just making sure that EFI programs can start, print output
>>> and exit. It is a test that we can easily run without a lot of
>>> overhead, much less than a full distro boot.
>>
>> Again, I don't think it's much more overhead and I do believe it gives
>> us much cleaner separation between responsibilities of code (tests go
>> where tests are).
>
> You are talking about a functional test, something that tests things
> end to end. I prefer to at least start with a smaller test. Granted it
> takes a little more work but it means there are fewer things to hunt
> through when something goes wrong.

Yes, I personally find unit tests terribly annoying and unproductive and 
functional tests very helpful :). And in this case, the effort to write 
it is about the same for both, just that the functional test actually 
tells you that things work or don't work at the end of the day.

With a code base like U-Boot, a simple functional test like the above 
plus git bisect should get you to an offending patch very quickly.


Alex