test: increase coverage for http2.connect

Added checks for connecting using https and an unsupported protocol.

PR-URL: https://github.com/nodejs/node/pull/14832
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

test/parallel/test-http2-connect.js

@@ -1,14 +1,14 @@
 // Flags: --expose-http2
 'use strict';
 
-const { mustCall, hasCrypto, skip } = require('../common');
+const { mustCall, hasCrypto, skip, expectsError } = require('../common');
 if (!hasCrypto)
   skip('missing crypto');
-const { doesNotThrow } = require('assert');
+const { doesNotThrow, throws } = require('assert');
 const { createServer, connect } = require('http2');
-
-const server = createServer();
-server.listen(0, mustCall(() => {
+{
+  const server = createServer();
+  server.listen(0, mustCall(() => {
     const authority = `http://localhost:${server.address().port}`;
     const options = {};
     const listener = () => mustCall();
@@ -28,4 +28,22 @@ server.listen(0, mustCall(() => {
         }
       }));
     }
-}));
+  }));
+}
+
+// check for https as protocol
+{
+  const authority = 'https://localhost';
+  doesNotThrow(() => connect(authority));
+}
+
+// check for error for an invalid protocol (not http or https)
+{
+  const authority = 'ssh://localhost';
+  throws(() => {
+    connect(authority);
+  }, expectsError({
+    code: 'ERR_HTTP2_UNSUPPORTED_PROTOCOL',
+    type: Error
+  }));
+}