build-system/go: Add test-subdirs option key.

Golang projects may contain subdirectories with test files, which can't
be reached by providing just IMPORT-PATH to the test runner.  This
change implements a TEST-SUBDIRS key parameter which is by default set
to "import-path/..." to run all available tests in the project, and may
be limited to particular subdirs list.

* guix/build-system/go.scm (go-build, go-cross-build): Add "test-subdirs"
key parameter.
* guix/build/go-build-system.scm (check): Add "test-subdirs" key
parameter and adjust test invokation accordingly.

Change-Id: Ibc107deea060f0d71e6f4e1e37c81d3b7c9992f5

guix/build-system/go.scm

@@ -205,6 +205,7 @@ (define* (go-build name inputs
                    (build-flags ''())
                    (tests? #t)
                    (test-flags ''())
+                   (test-subdirs ''("..."))
                    (parallel-build? #t)
                    (parallel-tests? #t)
                    (allow-go-reference? #f)
@@ -239,6 +240,7 @@ (define builder
                     #:build-flags #$build-flags
                     #:tests? #$tests?
                     #:test-flags #$test-flags
+                    #:test-subdirs #$test-subdirs
                     #:parallel-build? #$parallel-build?
                     #:parallel-tests? #$parallel-tests?
                     #:allow-go-reference? #$allow-go-reference?
@@ -264,6 +266,7 @@ (define* (go-cross-build name
                          (build-flags ''())
                          (tests? #f)              ; nothing can be done
                          (test-flags ''())
+                         (test-subdirs ''("..."))
                          (allow-go-reference? #f)
                          (system (%current-system))
                          (goarch (first (go-target target)))
@@ -316,6 +319,7 @@ (define %outputs
                     #:build-flags #$build-flags
                     #:tests? #$tests?
                     #:test-flags #$test-flags
+                    #:test-subdirs #$test-subdirs
                     #:make-dynamic-linker-cache? #f ;cross-compiling
                     #:allow-go-reference? #$allow-go-reference?
                     #:inputs %build-inputs))))

guix/build/go-build-system.scm

@@ -98,6 +98,10 @@ (define-module (guix build go-build-system)
 ;; * Remove module packages, only offering the full Git repos? This is
 ;; more idiomatic, I think, because Go downloads Git repos, not modules.
 ;; What are the trade-offs?
+;; * Figurie out how to passthrough --verbosity option to "build" and "check"
+;; procedures.
+;; * Implement test-backend option, which would be similar to pyproject's
+;; one, allowing to provide custom test runner.
 ;;
 ;; [0] `go build`:
 ;; https://golang.org/cmd/go/#hdr-Compile_packages_and_dependencies
@@ -326,13 +330,23 @@ (define* (build #:key
                               "Here are the results of `go env`:\n"))
       (invoke "go" "env"))))
 
-(define* (check #:key tests? import-path test-flags (parallel-tests? #t)
+(define* (check #:key
+                tests?
+                import-path
+                test-flags
+                test-subdirs
+                (parallel-tests? #t)
                 #:allow-other-keys)
   "Run the tests for the package named by IMPORT-PATH."
   (when tests?
     (let* ((njobs (if parallel-tests? (parallel-job-count) 1)))
       (setenv "GOMAXPROCS" (number->string njobs)))
-    (apply invoke "go" "test" `(,import-path ,@test-flags)))
+    (apply invoke "go" "test"
+           `(,@(map (lambda (dir)
+                      (format #f "~a~:[/~;~]~a"
+                              import-path (string-null? dir) dir))
+                    test-subdirs)
+             ,@test-flags)))
   #t)
 
 (define* (install #:key install-source? outputs import-path unpack-path #:allow-other-keys)