Merge branch 'sg/test-BUG'

test framework has been updated to make a bug in the test script
(as opposed to bugs in Git that are discovered by running the
tests) stand out more prominently.

* sg/test-BUG:
tests: send "bug in the test script" errors to the script's stderr

diff --combined t/test-lib-functions.sh
index 589d93d15b4d7fa3021d34448364981cd7b68bdf,3c6bf8d8556ec0f6b512dd2550ec520b119f975a..6b3bbf99e46cf7cc418eca1eaf768d526ac658aa
--- 1/t/test-lib-functions.sh
--- 2/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@@ -418,14 -418,14 +418,14 @@@ test_declared_prereq () 
  test_verify_prereq () {
        test -z "$test_prereq" ||
        expr >/dev/null "$test_prereq" : '[A-Z0-9_,!]*$' ||
-       error "bug in the test script: '$test_prereq' does not look like a prereq"
+       BUG "'$test_prereq' does not look like a prereq"
  }
  
  test_expect_failure () {
        test_start_
        test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
        test "$#" = 2 ||
-       error "bug in the test script: not 2 or 3 parameters to test-expect-failure"
+       BUG "not 2 or 3 parameters to test-expect-failure"
        test_verify_prereq
        export test_prereq
        if ! test_skip "$@"
@@@ -445,7 -445,7 +445,7 @@@ test_expect_success () 
        test_start_
        test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
        test "$#" = 2 ||
-       error "bug in the test script: not 2 or 3 parameters to test-expect-success"
+       BUG "not 2 or 3 parameters to test-expect-success"
        test_verify_prereq
        export test_prereq
        if ! test_skip "$@"
@@@ -472,7 -472,7 +472,7 @@@
  test_external () {
        test "$#" = 4 && { test_prereq=$1; shift; } || test_prereq=
        test "$#" = 3 ||
-       error >&5 "bug in the test script: not 3 or 4 parameters to test_external"
+       BUG "not 3 or 4 parameters to test_external"
        descr="$1"
        shift
        test_verify_prereq
@@@ -613,7 -613,7 +613,7 @@@ test_path_is_missing () 
  test_line_count () {
        if test $# != 3
        then
-               error "bug in the test script: not 3 parameters to test_line_count"
+               BUG "not 3 parameters to test_line_count"
        elif ! test $(wc -l <"$3") "$1" "$2"
        then
                echo "test_line_count: line count for $3 !$1 $2"
@@@ -793,13 -793,12 +793,12 @@@ test_i18ngrep () 
        eval "last_arg=\${$#}"
  
        test -f "$last_arg" ||
-       error "bug in the test script: test_i18ngrep requires a file" \
-             "to read as the last parameter"
+       BUG "test_i18ngrep requires a file to read as the last parameter"
  
        if test $# -lt 2 ||
           { test "x!" = "x$1" && test $# -lt 3 ; }
        then
-               error "bug in the test script: too few parameters to test_i18ngrep"
+               BUG "too few parameters to test_i18ngrep"
        fi
  
        if test_have_prereq !C_LOCALE_OUTPUT
@@@ -854,23 -853,9 +853,23 @@@ test_must_be_empty () 
  
  # Tests that its two parameters refer to the same revision
  test_cmp_rev () {
 -      git rev-parse --verify "$1" >expect.rev &&
 -      git rev-parse --verify "$2" >actual.rev &&
 -      test_cmp expect.rev actual.rev
 +      if test $# != 2
 +      then
 +              error "bug in the test script: test_cmp_rev requires two revisions, but got $#"
 +      else
 +              local r1 r2
 +              r1=$(git rev-parse --verify "$1") &&
 +              r2=$(git rev-parse --verify "$2") &&
 +              if test "$r1" != "$r2"
 +              then
 +                      cat >&4 <<-EOF
 +                      error: two revisions point to different objects:
 +                        '$1': $r1
 +                        '$2': $r2
 +                      EOF
 +                      return 1
 +              fi
 +      fi
  }
  
  # Print a sequence of integers in increasing order, either with
@@@ -885,7 -870,7 +884,7 @@@ test_seq () 
        case $# in
        1)      set 1 "$@" ;;
        2)      ;;
-       *)      error "bug in the test script: not 1 or 2 parameters to test_seq" ;;
+       *)      BUG "not 1 or 2 parameters to test_seq" ;;
        esac
        test_seq_counter__=$1
        while test "$test_seq_counter__" -le "$2"
@@@ -923,7 -908,7 +922,7 @@@ test_when_finished () 
        # doing so on Bash is better than nothing (the test will
        # silently pass on other shells).
        test "${BASH_SUBSHELL-0}" = 0 ||
-       error "bug in test script: test_when_finished does nothing in a subshell"
+       BUG "test_when_finished does nothing in a subshell"
        test_cleanup="{ $*
                } && (exit \"\$eval_ret\"); eval_ret=\$?; $test_cleanup"
  }
@@@ -932,7 -917,7 +931,7 @@@
  # Usage: test_create_repo <directory>
  test_create_repo () {
        test "$#" = 1 ||
-       error "bug in the test script: not 1 parameter to test-create-repo"
+       BUG "not 1 parameter to test-create-repo"
        repo="$1"
        mkdir -p "$repo"
        (
@@@ -1245,7 -1230,7 +1244,7 @@@ test_oid_cache () 
  
                if ! expr "$k" : '[a-z0-9][a-z0-9]*$' >/dev/null
                then
-                       error 'bug in the test script: bad hash algorithm'
+                       BUG 'bad hash algorithm'
                fi &&
                eval "test_oid_${k}_$tag=\"\$v\""
        done
@@@ -1260,7 -1245,7 +1259,7 @@@ test_oid () 
        # key-hash pair, so exit with an error.
        if eval "test -z \"\${$var+set}\""
        then
-               error "bug in the test script: undefined key '$1'" >&2
+               BUG "undefined key '$1'"
        fi &&
        eval "printf '%s' \"\${$var}\""
  }