t: prepare execution of potentially failing commands for set -e

Several of our tests verify whether a certain binary can be executed,
potentially skipping tests in case we cannot, for example because the
binary doesn't exist. In those cases we often run the binary outside of
any conditionally.

This will start to fail once we enable `set -e`, as that will cause us
to bail out the test immediately. Improve these tests by executing them
inside of a conditional instead.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

t/lib-git-svn.sh

@@ -15,8 +15,7 @@ GIT_SVN_DIR=$GIT_DIR/svn/refs/remotes/git-svn
 SVN_TREE=$GIT_SVN_DIR/svn-tree
 test_set_port SVNSERVE_PORT
 
-svn >/dev/null 2>&1
-if test $? -ne 1
+if ! svn help >/dev/null 2>&1
 then
 	skip_all='skipping git svn tests, svn not found'
 	test_done

t/lib-httpd.sh

@@ -235,11 +235,10 @@ start_httpd() {
 
 	test_atexit stop_httpd
 
-	"$LIB_HTTPD_PATH" -d "$HTTPD_ROOT_PATH" \
+	if ! "$LIB_HTTPD_PATH" -d "$HTTPD_ROOT_PATH" \
 		-f "$TEST_PATH/apache.conf" $HTTPD_PARA \
 		-c "Listen 127.0.0.1:$LIB_HTTPD_PORT" -k start \
 		>&3 2>&4
-	if test $? -ne 0
 	then
 		cat "$HTTPD_ROOT_PATH"/error.log >&4 2>/dev/null
 		test_skip_or_die GIT_TEST_HTTPD "web server setup failed"

t/t9200-git-cvsexportcommit.sh

@@ -11,8 +11,7 @@ if ! test_have_prereq PERL; then
 	test_done
 fi
 
-cvs >/dev/null 2>&1
-if test $? -ne 1
+if ! cvs version >/dev/null 2>&1
 then
     skip_all='skipping git cvsexportcommit tests, cvs not found'
     test_done

t/t9400-git-cvsserver-server.sh

@@ -17,12 +17,13 @@ if ! test_have_prereq PERL; then
 	skip_all='skipping git cvsserver tests, perl not available'
 	test_done
 fi
-cvs >/dev/null 2>&1
-if test $? -ne 1
+
+if ! cvs version >/dev/null 2>&1
 then
     skip_all='skipping git-cvsserver tests, cvs not found'
     test_done
 fi
+
 perl -e 'use DBI; use DBD::SQLite' >/dev/null 2>&1 || {
     skip_all='skipping git-cvsserver tests, Perl SQLite interface unavailable'
     test_done

t/t9401-git-cvsserver-crlf.sh

@@ -60,12 +60,12 @@ check_status_options() {
     return $stat
 }
 
-cvs >/dev/null 2>&1
-if test $? -ne 1
+if ! cvs version >/dev/null 2>&1
 then
     skip_all='skipping git-cvsserver tests, cvs not found'
     test_done
 fi
+
 if ! test_have_prereq PERL
 then
     skip_all='skipping git-cvsserver tests, perl not available'

t/t9402-git-cvsserver-refs.sh

@@ -68,12 +68,12 @@ check_diff() {
 
 #########
 
-cvs >/dev/null 2>&1
-if test $? -ne 1
+if ! cvs version >/dev/null 2>&1
 then
 	skip_all='skipping git-cvsserver tests, cvs not found'
 	test_done
 fi
+
 if ! test_have_prereq PERL
 then
 	skip_all='skipping git-cvsserver tests, perl not available'

t/test-lib.sh

@@ -143,8 +143,8 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 ################################################################
 # It appears that people try to run tests without building...
 GIT_BINARY="${GIT_TEST_INSTALLED:-$GIT_BUILD_DIR}/git$X"
-"$GIT_BINARY" >/dev/null
-if test $? != 1
+
+if ! "$GIT_BINARY" version >/dev/null
 then
 	if test -n "$GIT_TEST_INSTALLED"
 	then