tests: Skip network-dependent tests when the network is unreachable.

* tests/builders.scm (network-reachable?): New variable.
  ("url-fetch", "gnu-build"): Skip unless NETWORK-REACHABLE?.
* tests/derivations.scm (%coreutils): Check for network access.
  ("build-expression->derivation with one input"): Skip when %COREUTILS
  is #f.
* tests/guix-package.sh: Skip installation of GNU Make when the network
  is unreachable.
* tests/packages.scm ("GNU Make, bootstrap"): Likewise.
* tests/union.scm ("union-build"): Likewise.

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/builders.scm b/tests/builders.scm
index 12841d56902..6035032d5d0 100644
--- a/tests/builders.scm
+++ b/tests/builders.scm
@@ -50,9 +50,13 @@
               (list name (package-derivation %store package))))
             (@@ (distro packages base) %boot0-inputs))))
 
+(define network-reachable?
+  (false-if-exception (getaddrinfo "www.gnu.org" "80" AI_NUMERICSERV)))
+
 
 (test-begin "builders")
 
+(unless network-reachable? (test-skip 1))
 (test-assert "url-fetch"
   (let* ((url      '("http://ftp.gnu.org/gnu/hello/hello-2.8.tar.gz"
                      "ftp://ftp.gnu.org/gnu/hello/hello-2.8.tar.gz"))
@@ -69,6 +73,7 @@
   (and (build-system? gnu-build-system)
        (eq? gnu-build (build-system-builder gnu-build-system))))
 
+(unless network-reachable? (test-skip 1))
 (test-assert "gnu-build"
   (let* ((url      "http://ftp.gnu.org/gnu/hello/hello-2.8.tar.gz")
          (hash     (nix-base32-string->bytevector