make test.(ba)sh less annoying

.gitignore

@@ -1,4 +1,5 @@
 *.o
 test
+!test/
 .ninja_deps
 .ninja_log

README.md

@@ -24,8 +24,7 @@ It is required that one file in your project defines the
 as with any other single-header library.
 
 An example for how to use readarg can be found in `test/test.c`. If you want to
-see how readarg represents options and operands, execute `test.sh` in the same
-directory.
+see how readarg represents options and operands, run `test.bash`.
 
 ## Terminology
 

test/test.bash

@@ -1,4 +1,7 @@
-#!/bin/sh
+#!/usr/bin/env bash
+
+cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &> /dev/null
+
 ./test \
 	-e a \
 	--expr b \