Add good stack traces tests and fix stack traces in debug mode

lib/command.js

@@ -1,7 +1,6 @@
 'use strict';
 
-var debug_mode = require('../').debug_mode;
-var betterStackTraces = process.env.NODE_ENV && process.env.NODE_ENV.toUpperCase() === 'DEVELOPMENT' || debug_mode;
+var betterStackTraces = /development/i.test(process.env.NODE_ENV) || /\bredis\b/i.test(process.env.NODE_DEBUG);
 
 function Command (command, args, callback, call_on_write) {
     this.command = command;

test/good_traces.spec.js

@@ -0,0 +1,59 @@
+'use strict';
+
+var assert = require('assert');
+var config = require('./lib/config');
+var fork = require('child_process').fork;
+var redis = config.redis;
+
+describe('stack traces', function () {
+
+    it('should return good traces with NODE_ENV=development set', function (done) {
+        var external = fork('./test/lib/good-traces.js', {
+            env: {
+                NODE_ENV: 'development'
+            }
+        });
+
+        var id = setTimeout(function () {
+            external.kill();
+            done(new Error('Timeout'));
+        }, 6000);
+
+        external.on('close', function (code) {
+            clearTimeout(id);
+            assert.strictEqual(code, 0);
+            done();
+        });
+    });
+
+    it('should return good traces with NODE_DEBUG=redis env set', function (done) {
+        var external = fork('./test/lib/good-traces.js', {
+            env: {
+                NODE_DEBUG: 'redis'
+            },
+            silent: true
+        });
+
+        var id = setTimeout(function () {
+            external.kill();
+            done(new Error('Timeout'));
+        }, 6000);
+
+        external.on('close', function (code) {
+            clearTimeout(id);
+            assert.strictEqual(code, 0);
+            done();
+        });
+    });
+
+    // This is always going to return good stack traces
+    it('should always return good stack traces for rejected offline commands', function (done) {
+        var client = redis.createClient({
+            enable_offline_queue: false
+        });
+        client.set('foo', function (err, res) {
+            assert(/good_traces.spec.js/.test(err.stack));
+            client.quit(done);
+        });
+    });
+});

test/lib/good-traces.js

@@ -0,0 +1,20 @@
+// Spawned by the good_stacks.spec.js tests
+'use strict';
+
+var assert = require('assert');
+var redis = require('../../index');
+var client = redis.createClient();
+
+// Both error cases would normally return bad stack traces
+client.set('foo', function (err, res) {
+    assert(/good-traces.js:9:8/.test(err.stack));
+    client.set('foo', 'bar', function (err, res) {
+        assert(/good-traces.js:11:12/.test(err.stack));
+        client.quit(function () {
+            process.exit(0);
+        });
+    });
+    process.nextTick(function () {
+        client.stream.destroy();
+    });
+});

test/node_redis.spec.js

@@ -851,7 +851,7 @@ describe('The node_redis client', function () {
 
                     var id = setTimeout(function () {
                         external.kill();
-                        done(Error('unref subprocess timed out'));
+                        done(new Error('unref subprocess timed out'));
                     }, 8000);
 
                     external.on('close', function (code) {