test: add test case to test-http-response-statuscode.js

Change regular expression of error message.
Add test case(`res.writeHead()`).

PR-URL: #10808
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/parallel/test-http-response-statuscode.js

@@ -3,70 +3,79 @@ const common = require('../common');
 const assert = require('assert');
 const http = require('http');
 
-const MAX_REQUESTS = 12;
-var reqNum = 0;
+const MAX_REQUESTS = 13;
+let reqNum = 0;
+
+const createErrorMessage = (code) => {
+  return new RegExp(`^RangeError: Invalid status code: ${code}$`);
+};
 
 const server = http.Server(common.mustCall(function(req, res) {
   switch (reqNum) {
     case 0:
       assert.throws(common.mustCall(() => {
         res.writeHead(-1);
-      }), /invalid status code/i);
+      }), createErrorMessage(-1));
       break;
     case 1:
       assert.throws(common.mustCall(() => {
         res.writeHead(Infinity);
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
       break;
     case 2:
       assert.throws(common.mustCall(() => {
         res.writeHead(NaN);
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
       break;
     case 3:
       assert.throws(common.mustCall(() => {
         res.writeHead({});
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
       break;
     case 4:
       assert.throws(common.mustCall(() => {
         res.writeHead(99);
-      }), /invalid status code/i);
+      }), createErrorMessage(99));
       break;
     case 5:
       assert.throws(common.mustCall(() => {
         res.writeHead(1000);
-      }), /invalid status code/i);
+      }), createErrorMessage(1000));
       break;
     case 6:
       assert.throws(common.mustCall(() => {
         res.writeHead('1000');
-      }), /invalid status code/i);
+      }), createErrorMessage(1000));
       break;
     case 7:
       assert.throws(common.mustCall(() => {
         res.writeHead(null);
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
       break;
     case 8:
       assert.throws(common.mustCall(() => {
         res.writeHead(true);
-      }), /invalid status code/i);
+      }), createErrorMessage(1));
       break;
     case 9:
       assert.throws(common.mustCall(() => {
         res.writeHead([]);
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
       break;
     case 10:
       assert.throws(common.mustCall(() => {
         res.writeHead('this is not valid');
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
       break;
     case 11:
       assert.throws(common.mustCall(() => {
         res.writeHead('404 this is not valid either');
-      }), /invalid status code/i);
+      }), createErrorMessage(0));
+      break;
+    case 12:
+      assert.throws(common.mustCall(() => {
+        res.writeHead();
+      }), createErrorMessage(0));
       this.close();
       break;
     default: