tests: use variable for test name in weston-tests-env

Slightly more readable and makes it easier to switch to use $2 for something
in the future (if that's ever needed).

tests/weston-tests-env

@@ -1,5 +1,12 @@
 #!/bin/bash
 
+TESTNAME=$1
+
+if test -z "$TESTNAME"; then
+	echo "usage: $(basename $0) <test name>"
+	exit 1;
+fi
+
 WESTON=$abs_builddir/../src/weston
 LOGDIR=$abs_builddir/logs
 
@@ -18,17 +25,17 @@ else
 	BACKEND=$abs_builddir/../src/.libs/wayland-backend.so
 fi
 
-case $1 in
+case $TESTNAME in
 	*.la|*.so)
 		$WESTON --backend=$BACKEND \
-			--socket=test-$(basename $1) \
-			--modules=$abs_builddir/.libs/${1/.la/.so},xwayland.so \
+			--socket=test-$(basename $TESTNAME) \
+			--modules=$abs_builddir/.libs/${TESTNAME/.la/.so},xwayland.so \
 			--log="$SERVERLOG" \
 			&> "$OUTLOG"
 		;;
 	*)
-		WESTON_TEST_CLIENT_PATH=$abs_builddir/$1 $WESTON \
-			--socket=test-$(basename $1) \
+		WESTON_TEST_CLIENT_PATH=$abs_builddir/$TESTNAME $WESTON \
+			--socket=test-$(basename $TESTNAME) \
 			--backend=$BACKEND \
 			--log="$SERVERLOG" \
 			--modules=$abs_builddir/.libs/weston-test.so,xwayland.so \