size: Add test to multiple 'store-profile' arguments.

* tests/size.scm ("store-profile with multiple items"): New test.

tests/size.scm

 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -86,6 +86,22 @@ (define (lookup-profile item)
                                     (profile-self-size profile3)
                                     (profile-self-size profile4))))))))))))
 
+(test-assertm "store-profile with multiple items"
+  (mlet* %store-monad ((file1 (gexp->derivation "file1"
+                                                #~(symlink #$%bootstrap-guile
+                                                           #$output)))
+                       (file2 (text-file* "file2"
+                                          "the file => " file1)))
+    (mbegin %store-monad
+      (built-derivations (list file2))
+      (mlet %store-monad ((profiles  (store-profile
+                                      (list (derivation->output-path file2)
+                                            (derivation->output-path file1))))
+                          (reference (store-profile
+                                      (list (derivation->output-path file2)))))
+        (return (and (= (length profiles) 4)
+                     (lset= equal? profiles reference)))))))
+
 (test-end "size")
 
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