diff --git a/package.json b/package.json
index ffcea58..7f2e25b 100644
--- a/package.json
+++ b/package.json
@@ -16,6 +16,7 @@
   "author": "Fedor Indutny <fedor@indutny.com>",
   "license": "MIT",
   "devDependencies": {
+    "debug": "^2.6.1",
     "eslint": "^2.12.0",
     "mocha": "^2.5.3",
     "ninja.js": "^1.1.0",
diff --git a/test/gyppies-test.js b/test/gyppies-test.js
index 7752a67..c5ff3f7 100644
--- a/test/gyppies-test.js
+++ b/test/gyppies-test.js
@@ -8,6 +8,7 @@ const path = require('path');
 const rimraf = require('rimraf');
 const ninja = require('ninja.js');
 const spawnSync = require('child_process').spawnSync;
+const debug = require('debug')('gyp.js');
 
 const rootDir = path.join(__dirname, '..');
 const gyp = path.join(rootDir, 'bin', 'gyp');
@@ -35,9 +36,11 @@ function build(name) {
     if (process.env.running_under_istanbul)
       argv = istanbulArgs.concat(argv);
 
+    debug({execPath: process.execPath, argv, spawnOpts});
     let p = spawnSync(process.execPath, argv, spawnOpts);
     if (p.status !== 0 && p.stdout)
       console.error(p.stdout.toString());
+    debug(p.stdout.toString());
     if (p.error)
       throw p.error;
     assert.equal(p.status, 0, `cd ${name} && gyp failed`);