break up big output test into two sets

otherwise this thing times out a lot

Author: isaacs

test/test-am.js

@@ -0,0 +1,2 @@
+var runTests = require('./test.js')
+runTests('[a-m]*.js')

test/test-nz.js

@@ -0,0 +1,2 @@
+var runTests = require('./test.js')
+runTests('[n-z]*.js')

test/test.js

@@ -11,11 +11,17 @@ function regEsc (str) {
   return str.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, '\\$&')
 }
 
-if (process.argv[2]) {
-  var file = path.resolve(dir, process.argv[2])
-  runTests(file)
-} else {
-  glob.sync(dir + '*.js').forEach(runTests)
+if (module === require.main) {
+  if (process.argv[2]) {
+    var file = path.resolve(dir, process.argv[2])
+    runTests(file)
+  } else {
+    t.pass('just a common file')
+  }
+}
+
+module.exports = function (pattern) {
+  glob.sync(dir + pattern).forEach(runTests)
 }
 
 function runTests (file) {