split up output tests by type, not name

Juggling the alphabet is too hard as the number of tests and cases
increases.  Passing two booleans to a function feels like it should
probably be an options object, but whatever.  We can cross that bridge
later.

Also, this allows running a single case in an ad-hoc manner which is a
bit more convenient in development.

test/test-output-am.js → test/test-bail-buffer.js

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

test/test-output-nz.js → test/test-bail.js

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

test/test-buffer.js

@@ -0,0 +1,2 @@
+var runTests = require('./test.js')
+runTests('*.js', false, true)

test/test.js

@@ -11,19 +11,41 @@ function regEsc (str) {
   return str.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, '\\$&')
 }
 
-module.exports = function (pattern) {
-  glob.sync(dir + pattern).forEach(runTests)
+module.exports = function (pattern, bail, buffer) {
+  glob.sync(dir + pattern).forEach(function (f) {
+    runTests(f, bail, buffer)
+  })
 }
 
 if (module === require.main) {
   if (process.argv[2]) {
-    module.exports(process.argv[2])
+    var bail, buffer
+    process.argv.slice(3).forEach(function (x) {
+      switch (x) {
+        case 'bail': return bail = true
+        case 'buffer': return buffer = true
+        case 'nobail': return bail = false
+        case 'nobuffer': return buffer = false
+      }
+    })
+    module.exports(process.argv[2], bail, buffer)
   } else {
-    t.pass('just a common file')
+    module.exports('*.js', false, false)
   }
 }
 
-function runTests (file) {
+function runTests (file, bail, buffer) {
+  var bails = [ !!bail ]
+  var buffs = [ !!buffer ]
+
+  if (bail === undefined) {
+    bails = [ true, false ]
+  }
+
+  if (buffer === undefined) {
+    buffs = [ true, false ]
+  }
+
   var skip = false
   if (file.match(/\b(timeout.*|pending-handles)\.js$/)) {
     if (process.env.TRAVIS) {
@@ -43,9 +65,7 @@ function runTests (file) {
 
   var f = file.substr(dir.length)
   t.test(f, { skip: skip }, function (t) {
-    var bails = [ true, false ]
-    var buffs = [ true, false ]
-    t.plan(4)
+    t.plan(bails.length * buffs.length)
     bails.forEach(function (bail) {
       buffs.forEach(function (buff) {
         t.test('bail=' + bail + ' buffer=' + buff, function (t) {