Running individual system tests

[Daniel Schäfer]

Hi Guix,

Guix System has nice system tests, as described in [1] but they don't 
easily allow to run a single test.

The manual says to run `make check-system TESTS="basic mcron"` in the 
guix source tree.
That, however, (apparently) requires to be bootstrapped, configured and 
all Scheme files to be fully built.

Is there something as simple as:

$ guix build -f gnu/tests/rsync.scm
guix build: error: #<unspecified>: not something we can build

---

I hacked together a solution that works but is far from nice.
It is based off of build-aux/run-system-tests.scm and I tried to strip 
it down to the core.

$ cat run-test.scm
(use-modules (gnu tests rsync)
             (gnu tests)
             (guix store)
             (guix status)
             (guix monads)
             (guix derivations)
             (guix ui)
             (srfi srfi-1)
             (srfi srfi-34))

(define (built-derivations* drv)
  (lambda (store)
    (guard (c ((store-protocol-error? c)
               (values #f store)))
      (values (build-derivations store drv) store))))

(system-test-value %test-rsync)
  (with-store store
    (with-status-verbosity 2
      (run-with-store store
        (mlet* %store-monad ((drv (mapm %store-monad system-test-value 
(list %test-rsync)))
                             (out -> (map derivation->output-path drv)))
          (mbegin %store-monad
            (show-what-to-build* drv)
            (set-build-options* #:keep-going? #t #:keep-failed? #t
                                #:print-build-trace #t
                                #:print-extended-build-trace? #t
                                #:fallback? #t)
            (built-derivations* drv)
            (display out))))))

$ guile -s run-test.scm
(/gnu/store/scifaigbvcj20lplj3mvqj3ndr9w0nlv-rsync-test)Backtrace:
           8 (apply-smob/1 #<catch-closure 7353e0>)
In ice-9/boot-9.scm:
    705:2  7 (call-with-prompt _ _ #<procedure default-prompt-handle…>)
In ice-9/eval.scm:
    619:8  6 (_ #(#(#<directory (guile-user) 7cd140>)))
In ice-9/boot-9.scm:
   2312:4  5 (save-module-excursion _)
  3831:12  4 (_)
In /home/zoid/guix/gnu/tests/run-test.scm:
     19:4  3 (_)
In guix/status.scm:
    810:4  2 (call-with-status-report _ _)
In guix/store.scm:
  1737:24  1 (run-with-store _ _ #:guile-for-build _ #:system _ # _)
In unknown file:
           0 (_ #<store-connection 256.99 3b8dd20>)

ERROR: Wrong type to apply: #<unspecified>


It shows the derivation output path before the backtrace and thus I can 
inspect the log.
Can I do this in a nicer way?
It would be very helpful for out-of-tree system tests.

Thanks

- Daniel

[1] https://guix.gnu.org/blog/2016/guixsd-system-tests/