tests: optionally skip bin-wrappers/

This speeds up the tests by a bit on Windows, where running Unix shell
scripts (and spawning processes) is not exactly a cheap operation.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

t/README

@@ -170,6 +170,15 @@ appropriately before running "make".
 	implied by other options like --valgrind and
 	GIT_TEST_INSTALLED.
 
+--no-bin-wrappers::
+	By default, the test suite uses the wrappers in
+	`../bin-wrappers/` to execute `git` and friends. With this option,
+	`../git` and friends are run directly. This is not recommended
+	in general, as the wrappers contain safeguards to ensure that no
+	files from an installed Git are used, but can speed up test runs
+	especially on platforms where running shell scripts is expensive
+	(most notably, Windows).
+
 --root=<directory>::
 	Create "trash" directories used to store all temporary data during
 	testing under <directory>, instead of the t/ directory.

t/test-lib.sh

@@ -294,6 +294,8 @@ do
 		test -z "$HARNESS_ACTIVE" && quiet=t; shift ;;
 	--with-dashes)
 		with_dashes=t; shift ;;
+	--no-bin-wrappers)
+		no_bin_wrappers=t; shift ;;
 	--no-color)
 		color=; shift ;;
 	--va|--val|--valg|--valgr|--valgri|--valgrin|--valgrind)
@@ -1081,16 +1083,21 @@ then
 	PATH=$GIT_TEST_INSTALLED:$GIT_BUILD_DIR/t/helper:$PATH
 	GIT_EXEC_PATH=${GIT_TEST_EXEC_PATH:-$GIT_EXEC_PATH}
 else # normal case, use ../bin-wrappers only unless $with_dashes:
-	git_bin_dir="$GIT_BUILD_DIR/bin-wrappers"
-	if ! test -x "$git_bin_dir/git"
+	if test -n "$no_bin_wrappers"
 	then
-		if test -z "$with_dashes"
+		with_dashes=t
+	else
+		git_bin_dir="$GIT_BUILD_DIR/bin-wrappers"
+		if ! test -x "$git_bin_dir/git"
 		then
-			say "$git_bin_dir/git is not executable; using GIT_EXEC_PATH"
+			if test -z "$with_dashes"
+			then
+				say "$git_bin_dir/git is not executable; using GIT_EXEC_PATH"
+			fi
+			with_dashes=t
 		fi
-		with_dashes=t
+		PATH="$git_bin_dir:$PATH"
 	fi
-	PATH="$git_bin_dir:$PATH"
 	GIT_EXEC_PATH=$GIT_BUILD_DIR
 	if test -n "$with_dashes"
 	then