Added support for a hash token in the output parameter (#20)

* Added support for a hash token in the output parameter as 32 random hex chars

Co-authored-by: beezychru <christian.ruiz@beezy.net>

README.md

@@ -28,6 +28,7 @@ or you can set `MOCHA_REPORTER_FILE` environment var with the desired filename
 
 - **output** (string)
   Outputs as a TRX file into the provided path. If not provided, outputs to stdout.
+  The path can contain [hash], e.g. ./path_to_your/test-results.[hash].trx. [hash] is replaced by a random 32 hex char hash. This enables support of parallel execution of multiple mocha-trx-reporter's writing test results in separate files.
 - **treatPendingAsNotExecuted** (boolean)
   Pending tests (tests without implementation, or maked with `.skip`) have an  outcome of `NotExecuted` instead of
   `Pending` in the TRX file.

lib/trx.js

@@ -2,6 +2,7 @@ const fs = require('fs');
 const { reporters } = require('mocha');
 const { TestRun } = require('node-trx');
 const os = require('os');
+const crypto = require('crypto');
 const testToTrx = require('./test-to-trx');
 
 const computerName = os.hostname();
@@ -126,5 +127,9 @@ function ReporterTrx(runner, options) {
  * @returns {boolean|*}
  */
 function getFilename(reporterOptions) {
-    return reporterOptions.output || process.env.MOCHA_REPORTER_FILE;
+    let filePath = reporterOptions.output || process.env.MOCHA_REPORTER_FILE;
+    if (filePath && filePath.indexOf('[hash]') !== -1) {
+        filePath = filePath.replace('[hash]', crypto.randomBytes(16).toString('hex'));
+    }
+    return filePath;
 }