test: begin normalizing fixtures use

Adds a new `../common/fixtures' module to begin normalizing
`test/fixtures` use. Our test code is a bit inconsistent with
regards to use of the fixtures directory. Some code uses
`path.join()`, some code uses string concats, some other
code uses template strings, etc. In mnay cases, significant
duplication of code is seen when accessing fixture files, etc.

This updates many (but by no means all) of the tests in the
test suite to use the new consistent API. There are still
many more to update, which would make an excelent Code-n-Learn
exercise.

Author: jasnell

test/common/README.md

@@ -374,6 +374,37 @@ Decrements the `Countdown` counter.
 Specifies the remaining number of times `Countdown.prototype.dec()` must be
 called before the callback is invoked.
 
+## Fixtures Module
+
+The `common/fixtures` module provides convenience methods for working with
+files in the `test/fixtures` directory.
+
+### fixtures.fixturesDir
+
+* [<String>]
+
+The absolute path to the `test/fixtures/` directory.
+
+### fixtures.path(...args)
+
+* `...args` [<String>]
+
+Returns the result of `path.join(fixtures.fixturesDir, ...args)`.
+
+### fixtures.readSync(args[, enc])
+
+* `args` [<String>] | [<Array>]
+
+Returns the result of
+`fs.readFileSync(path.join(fixtures.fixturesDir, ...args), 'enc')`.
+
+### fixtures.readKey(arg[, enc])
+
+* `arg` [<String>]
+
+Returns the result of
+`fs.readFileSync(path.join(fixtures.fixturesDir, 'keys', arg), 'enc')`.
+
 ## WPT Module
 
 The wpt.js module is a port of parts of

test/common/fixtures.js

@@ -0,0 +1,28 @@
+/* eslint-disable required-modules */
+'use strict';
+
+const path = require('path');
+const fs = require('fs');
+
+const fixturesDir = path.join(__dirname, '..', 'fixtures');
+
+function fixturesPath(...args) {
+  return path.join(fixturesDir, ...args);
+}
+
+function readFixtureSync(args, enc) {
+  if (Array.isArray(args))
+    return fs.readFileSync(fixturesPath(...args), enc);
+  return fs.readFileSync(fixturesPath(args), enc);
+}
+
+function readFixtureKey(name, enc) {
+  return fs.readFileSync(fixturesPath('keys', name), enc);
+}
+
+module.exports = {
+  fixturesDir,
+  path: fixturesPath,
+  readSync: readFixtureSync,
+  readKey: readFixtureKey
+};

test/common/index.js

@@ -29,13 +29,15 @@ const { exec, execSync, spawn, spawnSync } = require('child_process');
 const stream = require('stream');
 const util = require('util');
 const Timer = process.binding('timer_wrap').Timer;
+const { fixturesDir } = require('./fixtures');
 
 const testRoot = process.env.NODE_TEST_DIR ?
   fs.realpathSync(process.env.NODE_TEST_DIR) : path.resolve(__dirname, '..');
 
 const noop = () => {};
 
-exports.fixturesDir = path.join(__dirname, '..', 'fixtures');
+exports.fixturesDir = fixturesDir;
+
 exports.tmpDirName = 'tmp';
 // PORT should match the definition in test/testpy/__init__.py.
 exports.PORT = +process.env.NODE_COMMON_PORT || 12346;

test/parallel/test-async-wrap-GH13045.js

@@ -8,12 +8,12 @@ if (!common.hasCrypto)
 
 const assert = require('assert');
 const https = require('https');
-const fs = require('fs');
+const fixtures = require('../common/fixtures');
 
 const serverOptions = {
-  key: fs.readFileSync(`${common.fixturesDir}/keys/agent1-key.pem`),
-  cert: fs.readFileSync(`${common.fixturesDir}/keys/agent1-cert.pem`),
-  ca: fs.readFileSync(`${common.fixturesDir}/keys/ca1-cert.pem`)
+  key: fixtures.readKey('agent1-key.pem'),
+  cert: fixtures.readKey('agent1-cert.pem'),
+  ca: fixtures.readKey('ca1-cert.pem')
 };
 
 const server = https.createServer(serverOptions, common.mustCall((req, res) => {

test/parallel/test-async-wrap-getasyncid.js

@@ -5,6 +5,7 @@ const assert = require('assert');
 const fs = require('fs');
 const net = require('net');
 const providers = Object.assign({}, process.binding('async_wrap').Providers);
+const fixtures = require('../common/fixtures');
 
 // Make sure that all Providers are tested.
 {
@@ -218,9 +219,10 @@ if (common.hasCrypto) {
   const TCP = process.binding('tcp_wrap').TCP;
   const tcp = new TCP();
 
-  const ca = fs.readFileSync(common.fixturesDir + '/test_ca.pem', 'ascii');
-  const cert = fs.readFileSync(common.fixturesDir + '/test_cert.pem', 'ascii');
-  const key = fs.readFileSync(common.fixturesDir + '/test_key.pem', 'ascii');
+  const ca = fixtures.readSync('test_ca.pem', 'ascii');
+  const cert = fixtures.readSync('test_cert.pem', 'ascii');
+  const key = fixtures.readSync('test_key.pem', 'ascii');
+
   const credentials = require('tls').createSecureContext({ ca, cert, key });
 
   // TLSWrap is exposed, but needs to be instantiated via tls_wrap.wrap().

test/parallel/test-child-process-detached.js

@@ -20,13 +20,12 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
-const common = require('../common');
+require('../common');
 const assert = require('assert');
-const path = require('path');
+const fixtures = require('../common/fixtures');
 
 const spawn = require('child_process').spawn;
-const childPath = path.join(common.fixturesDir,
-                            'parent-process-nonpersistent.js');
+const childPath = fixtures.path('parent-process-nonpersistent.js');
 let persistentPid = -1;
 
 const child = spawn(process.execPath, [ childPath ]);

test/parallel/test-child-process-execfile.js

@@ -2,10 +2,10 @@
 const common = require('../common');
 const assert = require('assert');
 const execFile = require('child_process').execFile;
-const path = require('path');
 const uv = process.binding('uv');
+const fixtures = require('../common/fixtures');
 
-const fixture = path.join(common.fixturesDir, 'exit.js');
+const fixture = fixtures.path('exit.js');
 
 {
   execFile(

test/parallel/test-child-process-exit-code.js

@@ -23,18 +23,17 @@
 const common = require('../common');
 const assert = require('assert');
 const spawn = require('child_process').spawn;
-const path = require('path');
+const fixtures = require('../common/fixtures');
 
-const exitScript = path.join(common.fixturesDir, 'exit.js');
+const exitScript = fixtures.path('exit.js');
 const exitChild = spawn(process.argv[0], [exitScript, 23]);
 exitChild.on('exit', common.mustCall(function(code, signal) {
   assert.strictEqual(code, 23);
   assert.strictEqual(signal, null);
 }));
 
 
-const errorScript = path.join(common.fixturesDir,
-                              'child_process_should_emit_error.js');
+const errorScript = fixtures.path('child_process_should_emit_error.js');
 const errorChild = spawn(process.argv[0], [errorScript]);
 errorChild.on('exit', common.mustCall(function(code, signal) {
   assert.ok(code !== 0);

test/parallel/test-child-process-fork-close.js

@@ -23,8 +23,9 @@
 const common = require('../common');
 const assert = require('assert');
 const fork = require('child_process').fork;
+const fixtures = require('../common/fixtures');
 
-const cp = fork(`${common.fixturesDir}/child-process-message-and-exit.js`);
+const cp = fork(fixtures.path('child-process-message-and-exit.js'));
 
 let gotMessage = false;
 let gotExit = false;

test/parallel/test-child-process-fork-stdio-string-variant.js

@@ -7,8 +7,9 @@ const common = require('../common');
 
 const assert = require('assert');
 const fork = require('child_process').fork;
+const fixtures = require('../common/fixtures');
 
-const childScript = `${common.fixturesDir}/child-process-spawn-node`;
+const childScript = fixtures.path('child-process-spawn-node');
 const errorRegexp = /^TypeError: Incorrect value of stdio option:/;
 const malFormedOpts = { stdio: '33' };
 const payload = { hello: 'world' };