hash: sha256 port now implements 'port-position'.

* guix/hash.scm (open-sha256-port)[position]: New variable.
[get-position]: New procedure.
Pass it to 'make-custom-binary-output-port'.
* tests/hash.scm ("open-sha256-port, hello"): Test 'port-position'.

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/hash.scm b/tests/hash.scm
index da87616eec..47dff3915b 100644
--- a/tests/hash.scm
+++ b/tests/hash.scm
@@ -64,12 +64,12 @@
     (get)))
 
 (test-equal "open-sha256-port, hello"
-  %hello-sha256
+  (list %hello-sha256 (string-length "hello world"))
   (let-values (((port get)
                 (open-sha256-port)))
     (put-bytevector port (string->utf8 "hello world"))
     (force-output port)
-    (get)))
+    (list (get) (port-position port))))
 
 (test-assert "port-sha256"
   (let* ((file     (search-path %load-path "ice-9/psyntax.scm"))