test: use mustCall() for simple flow tracking

Many of the tests use variables to track when callback functions
are invoked or events are emitted. These variables are then
asserted on process exit. This commit replaces this pattern in
straightforward cases with common.mustCall(). This makes the
tests easier to reason about, leads to a net reduction in lines
of code, and uncovered a few bugs in tests. This commit also
replaces some callbacks that should never be called with
common.fail().

PR-URL: https://github.com/nodejs/node/pull/7753
Reviewed-By: Wyatt Preul <wpreul@gmail.com>
Reviewed-By: Minwoo Jung <jmwsoft@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

4 files changed, 14 insertions, 55 deletions

diff --git a/test/internet/test-http-dns-fail.js b/test/internet/test-http-dns-fail.js
index 7e2f8cd402..c83b89f8cc 100644
--- a/test/internet/test-http-dns-fail.js
+++ b/test/internet/test-http-dns-fail.js
@@ -4,11 +4,10 @@
  * should trigger the error event after each attempt.
  */
 
-require('../common');
+const common = require('../common');
 var assert = require('assert');
 var http = require('http');
 
-var resDespiteError = false;
 var hadError = 0;
 
 function httpreq(count) {
@@ -19,9 +18,7 @@ function httpreq(count) {
     port: 80,
     path: '/',
     method: 'GET'
-  }, function(res) {
-    resDespiteError = true;
-  });
+  }, common.fail);
 
   req.on('error', function(e) {
     console.log(e.message);
@@ -37,6 +34,5 @@ httpreq(0);
 
 
 process.on('exit', function() {
-  assert.equal(false, resDespiteError);
   assert.equal(2, hadError);
 });
diff --git a/test/internet/test-http-https-default-ports.js b/test/internet/test-http-https-default-ports.js
index 33d5436733..8b00e434e9 100644
--- a/test/internet/test-http-https-default-ports.js
+++ b/test/internet/test-http-https-default-ports.js
@@ -1,6 +1,5 @@
 'use strict';
 var common = require('../common');
-var assert = require('assert');
 
 if (!common.hasCrypto) {
   common.skip('missing crypto');
@@ -9,21 +8,11 @@ if (!common.hasCrypto) {
 var https = require('https');
 
 var http = require('http');
-var gotHttpsResp = false;
-var gotHttpResp = false;
 
-process.on('exit', function() {
-  assert(gotHttpsResp);
-  assert(gotHttpResp);
-  console.log('ok');
-});
-
-https.get('https://www.google.com/', function(res) {
-  gotHttpsResp = true;
+https.get('https://www.google.com/', common.mustCall(function(res) {
   res.resume();
-});
+}));
 
-http.get('http://www.google.com/', function(res) {
-  gotHttpResp = true;
+http.get('http://www.google.com/', common.mustCall(function(res) {
   res.resume();
-});
+}));
diff --git a/test/internet/test-net-connect-timeout.js b/test/internet/test-net-connect-timeout.js
index fd78a2936b..0f58622aa1 100644
--- a/test/internet/test-net-connect-timeout.js
+++ b/test/internet/test-net-connect-timeout.js
@@ -3,16 +3,12 @@
 // https://groups.google.com/forum/#!topic/nodejs/UE0ZbfLt6t8
 // https://groups.google.com/forum/#!topic/nodejs-dev/jR7-5UDqXkw
 
-require('../common');
+const common = require('../common');
 var net = require('net');
 var assert = require('assert');
 
 var start = new Date();
 
-var gotTimeout = false;
-
-var gotConnect = false;
-
 var T = 100;
 
 // 192.0.2.1 is part of subnet assigned as "TEST-NET" in RFC 5737.
@@ -23,22 +19,11 @@ var socket = net.createConnection(9999, '192.0.2.1');
 
 socket.setTimeout(T);
 
-socket.on('timeout', function() {
+socket.on('timeout', common.mustCall(function() {
   console.error('timeout');
-  gotTimeout = true;
   var now = new Date();
   assert.ok(now - start < T + 500);
   socket.destroy();
-});
-
-socket.on('connect', function() {
-  console.error('connect');
-  gotConnect = true;
-  socket.destroy();
-});
-
+}));
 
-process.on('exit', function() {
-  assert.ok(gotTimeout);
-  assert.ok(!gotConnect);
-});
+socket.on('connect', common.fail);
diff --git a/test/internet/test-net-connect-unref.js b/test/internet/test-net-connect-unref.js
index ad24683b34..52929d2152 100644
--- a/test/internet/test-net-connect-unref.js
+++ b/test/internet/test-net-connect-unref.js
@@ -1,25 +1,14 @@
 'use strict';
-require('../common');
-var assert = require('assert');
+const common = require('../common');
 var net = require('net');
 
-var client, killed = false, ended = false;
+var client;
 var TIMEOUT = 10 * 1000;
 
 client = net.createConnection(53, '8.8.8.8', function() {
   client.unref();
 });
 
-client.on('close', function() {
-  ended = true;
-});
-
-setTimeout(function() {
-  killed = true;
-  client.end();
-}, TIMEOUT).unref();
+client.on('close', common.fail);
 
-process.on('exit', function() {
-  assert.strictEqual(killed, false, 'A client should have connected');
-  assert.strictEqual(ended, false, 'A client should stay connected');
-});
+setTimeout(common.fail, TIMEOUT).unref();