test: show more information in test-http2-debug upon failure

Use spawnSyncAndAssert() so that the stderr is logged when it
doesn't match expectations.

Author: joyeecheung

test/parallel/test-http2-debug.js

@@ -1,27 +1,33 @@
 'use strict';
+
 const common = require('../common');
 if (!common.hasCrypto)
   common.skip('missing crypto');
 const assert = require('assert');
-const child_process = require('child_process');
+const { spawnSyncAndAssert } = require('../common/child_process');
 const path = require('path');
 
-process.env.NODE_DEBUG_NATIVE = 'http2';
-process.env.NODE_DEBUG = 'http2';
-const { stdout, stderr } = child_process.spawnSync(process.execPath, [
+spawnSyncAndAssert(process.execPath, [
   path.resolve(__dirname, 'test-http2-ping.js'),
-], { encoding: 'utf8' });
+], {
+  env: {
+    ...process.env,
+    NODE_DEBUG: 'http2',
+    NODE_DEBUG_NATIVE: 'http2',
+  },
+},
+{
+  trim: true,
+  stderr(output) {
+    assert.match(output,
+      /Setting the NODE_DEBUG environment variable to 'http2' can expose sensitive data/);
+    assert.match(output, /\(such as passwords, tokens and authentication headers\) in the resulting log\.\r?\n/);
+    assert.match(output, /Http2Session client \(\d+\) handling data frame for stream \d+\r?\n/);
+    assert.match(output, /HttpStream \d+ \(\d+\) \[Http2Session client \(\d+\)\] reading starting\r?\n/);
+    assert.match(output, /HttpStream \d+ \(\d+\) \[Http2Session client \(\d+\)\] closed with code 0\r?\n/);
+    assert.match(output, /HttpStream \d+ \(\d+\) \[Http2Session server \(\d+\)\] closed with code 0\r?\n/);
+    assert.match(output, /HttpStream \d+ \(\d+\) \[Http2Session server \(\d+\)\] tearing down stream\r?\n/);
+  },
+  stdout: ''
+});
 
-assert(stderr.match(/Setting the NODE_DEBUG environment variable to 'http2' can expose sensitive data \(such as passwords, tokens and authentication headers\) in the resulting log\.\r?\n/),
-       stderr);
-assert(stderr.match(/Http2Session client \(\d+\) handling data frame for stream \d+\r?\n/),
-       stderr);
-assert(stderr.match(/HttpStream \d+ \(\d+\) \[Http2Session client \(\d+\)\] reading starting\r?\n/),
-       stderr);
-assert(stderr.match(/HttpStream \d+ \(\d+\) \[Http2Session client \(\d+\)\] closed with code 0\r?\n/),
-       stderr);
-assert(stderr.match(/HttpStream \d+ \(\d+\) \[Http2Session server \(\d+\)\] closed with code 0\r?\n/),
-       stderr);
-assert(stderr.match(/HttpStream \d+ \(\d+\) \[Http2Session server \(\d+\)\] tearing down stream\r?\n/),
-       stderr);
-assert.strictEqual(stdout.trim(), '');