test: refactor test-http-unix-socket

Use `common.mustCall()` and `common.fail()` where appropriate.
Change `assert.equal` to `assert.strictEqual` to ensure specificity.
Change var declarations to const to take advantage of ES6 immutable
bindings.
PR-URL: #10072
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

Author: davidmarkclements

test/parallel/test-http-unix-socket.js

@@ -1,9 +1,9 @@
 'use strict';
-varcommon=require('../common');
-varassert=require('assert');
-varhttp=require('http');
+constcommon=require('../common');
+constassert=require('assert');
+consthttp=require('http');
 
-varserver=http.createServer(function(req,res){
+constserver=http.createServer(function(req,res){
 res.writeHead(200,{
 'Content-Type': 'text/plain',
 'Connection': 'close'
@@ -23,8 +23,8 @@ server.listen(common.PIPE, common.mustCall(function() {
 };
 
 varreq=http.get(options,common.mustCall(function(res){
-assert.equal(res.statusCode,200);
-assert.equal(res.headers['content-type'],'text/plain');
+assert.strictEqual(res.statusCode,200);
+assert.strictEqual(res.headers['content-type'],'text/plain');
 
 res.body='';
 res.setEncoding('utf8');
@@ -34,19 +34,18 @@ server.listen(common.PIPE, common.mustCall(function() {
 });
 
 res.on('end',common.mustCall(function(){
-assert.equal(res.body,'hello world\n');
-server.close(function(error){
-assert.equal(error,undefined);
-server.close(function(error){
-assert.equal(error&&error.message,'Not running');
-});
-});
+assert.strictEqual(res.body,'hello world\n');
+server.close(common.mustCall(function(error){
+assert.strictEqual(error,undefined);
+server.close(common.mustCall(function(error){
+assert.strictEqual(error&&error.message,'Not running');
+}));
+}));
 }));
 }));
 
 req.on('error',function(e){
-console.log(e.stack);
-process.exit(1);
+common.fail(e.stack);
 });
 
 req.end();