Merge branch 'ab/fail-prereqs-in-test'

Developer support to emulate unsatisfied prerequisites in tests to
ensure that the remainer of the tests still succeeds when tests
with prerequisites are skipped.

* ab/fail-prereqs-in-test:
tests: add a special setup where prerequisites fail

diff --combined t/test-lib.sh
index 599fd70e141c7b7252b65ae6603486691864974b,6fabafebb31993506d5d026f36361e8877fb6eb0..4b346467df7aaf2e5215f7ebb3bfb4ae13a3ffbc
--- 1/t/test-lib.sh
--- 2/t/test-lib.sh
+++ b/t/test-lib.sh
@@@ -1522,7 -1522,7 +1522,7 @@@ test_lazy_prereq NOT_ROOT 
  '
  
  test_lazy_prereq JGIT '
 -      type jgit
 +      jgit --version
  '
  
  # SANITY is about "can you correctly predict what the filesystem would
@@@ -1607,3 -1607,7 +1607,7 @@@ test_lazy_prereq SHA1 
  test_lazy_prereq REBASE_P '
        test -z "$GIT_TEST_SKIP_REBASE_P"
  '
+ 
+ test_lazy_prereq FAIL_PREREQS '
+       test -n "$GIT_TEST_FAIL_PREREQS"
+ '