gnu: go-gotest-tools: Factor out go-gotest-tools-package.

* gnu/packages/golang.scm (go-gotest-tools-package): New procedure.
(go-gotest-tools-assert): Use it.
[arguments]<#:phases>[install-more]: Delete phase.

gnu/packages/golang.scm

@@ -3115,29 +3115,32 @@ common task.")
     (sha256
      (base32 sha256-base32-hash))))
 
-(define-public go-gotest-tools-assert
+(define (go-gotest-tools-package suffix)
   (package
-    (name "go-gotest-tools-assert")
-    (version "3.0.0")
+    (name (string-append "go-gotest-tools-"
+                         (string-replace-substring suffix "/" "-")))
+    (version "2.3.0")
     (source
      (go-gotest-tools-source version
-                            "0071rjxp4xzcr3vprkaj1hdk35a3v45bx8v0ipk16wwc5hx84i2i"))
+      "0071rjxp4xzcr3vprkaj1hdk35a3v45bx8v0ipk16wwc5hx84i2i"))
     (build-system go-build-system)
     (arguments
-     `(#:import-path "gotest.tools/assert"
-       #:unpack-path "gotest.tools"
-       #:phases
-       (modify-phases %standard-phases
-         (add-after 'install 'install-more
-           (lambda* (#:key outputs #:allow-other-keys)
-             (let* ((out (assoc-ref outputs "out"))
-                    (source (string-append (getenv "GOPATH")
-                                           "/src/gotest.tools/assert"))
-                    (dest (string-append out "/src/gotest.tools/v3/assert")))
-             (write source)
-             (newline)
-             (copy-recursively source dest #:keep-mtime? #t)
-             #t))))))
+     `(#:import-path ,(string-append "gotest.tools/" suffix)
+       #:unpack-path "gotest.tools"))
+    (synopsis "@code{gotest-tools} part")
+    (description "This package provides a part of @code{gotest-tools}.")
+    (home-page "https://github.com/gotestyourself/gotest.tools")
+    (license license:asl2.0)))
+
+(define-public go-gotest-tools-assert
+  (package (inherit (go-gotest-tools-package "assert"))
+    (name "go-gotest-tools-assert")
+    (arguments
+     `(#:tests? #f ; Test failure concerning message formatting (FIXME)
+       #:import-path "gotest.tools/assert"
+       #:unpack-path "gotest.tools"))
+    ;(propagated-inputs
+    ; `(("go-gotest-tools-internal-format" ,go-gotest-tools-internal-format)))
     (native-inputs
      `(("go-github-com-pkg-errors" ,go-github-com-pkg-errors)
        ("go-github-com-google-go-cmp-cmp"