http: change DEP0066 to a runtime deprecation

Change doc-only deprecation for _headers and _headerNames accessors to a
runtime deprecation.

PR-URL: https://github.com/nodejs/node/pull/24167
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

3 files changed, 31 insertions, 0 deletions

diff --git a/test/parallel/test-http-outgoing-internal-headernames-getter.js b/test/parallel/test-http-outgoing-internal-headernames-getter.js
new file mode 100644
index 0000000000..c8bd1f13d5
--- /dev/null
+++ b/test/parallel/test-http-outgoing-internal-headernames-getter.js
@@ -0,0 +1,13 @@
+'use strict';
+const common = require('../common');
+
+const { OutgoingMessage } = require('http');
+
+const warn = 'OutgoingMessage.prototype._headerNames is deprecated';
+common.expectWarning('DeprecationWarning', warn, 'DEP0066');
+
+{
+  // tests for _headerNames get method
+  const outgoingMessage = new OutgoingMessage();
+  outgoingMessage._headerNames;
+}
diff --git a/test/parallel/test-http-outgoing-internal-headernames-setter.js b/test/parallel/test-http-outgoing-internal-headernames-setter.js
new file mode 100644
index 0000000000..7329076698
--- /dev/null
+++ b/test/parallel/test-http-outgoing-internal-headernames-setter.js
@@ -0,0 +1,15 @@
+'use strict';
+const common = require('../common');
+
+const { OutgoingMessage } = require('http');
+
+const warn = 'OutgoingMessage.prototype._headerNames is deprecated';
+common.expectWarning('DeprecationWarning', warn, 'DEP0066');
+
+{
+  // tests for _headerNames set method
+  const outgoingMessage = new OutgoingMessage();
+  outgoingMessage._headerNames = {
+    'x-flow-id': '61bba6c5-28a3-4eab-9241-2ecaa6b6a1fd'
+  };
+}
diff --git a/test/parallel/test-http-outgoing-internal-headers.js b/test/parallel/test-http-outgoing-internal-headers.js
index de75a44e8a..2cebfe9e2b 100644
--- a/test/parallel/test-http-outgoing-internal-headers.js
+++ b/test/parallel/test-http-outgoing-internal-headers.js
@@ -6,6 +6,9 @@ const assert = require('assert');
 const { outHeadersKey } = require('internal/http');
 const { OutgoingMessage } = require('http');
 
+const warn = 'OutgoingMessage.prototype._headers is deprecated';
+common.expectWarning('DeprecationWarning', warn, 'DEP0066');
+
 {
   // tests for _headers get method
   const outgoingMessage = new OutgoingMessage();