Respond to TAP_DEBUG and NODE_DEBUG environs

Author: isaacs

bin/usage.txt

@@ -215,6 +215,10 @@ Environment Variables:
 
   _TAP_COVERAGE_              Reserved for internal use.
 
+  TAP_DEBUG                   Set to '1' to turn on debug mode.
+
+  NODE_DEBUG                  Include 'tap' to turn on debug mode.
+
 Config Files:
 
 You can create a yaml file with any of the options above.  By default,

lib/tap.js

@@ -111,7 +111,12 @@ TAP.prototype.teardown = TAP.prototype.tearDown = function (fn) {
   return Test.prototype.teardown.apply(this, arguments)
 }
 
-var tap = new TAP({ name: 'TAP' })
+var opt = { name: 'TAP' }
+if (process.env.TAP_DEBUG === '1' ||
+    /\btap\b/.test(process.env.NODE_DEBUG || ''))
+  opt.debug = true
+
+var tap = new TAP(opt)
 module.exports = tap
 tap.mocha = require('./mocha.js')
 tap.mochaGlobals = tap.mocha.global