Validate host contains scheme if it's passed

Author: ilyabe

Diff for: locust/main.py

@@ -13,6 +13,7 @@
 import sys
 import time
 import traceback
+from urllib.parse import urlparse
 
 import gevent
 
@@ -512,11 +513,7 @@ def assign_equal_weights(environment, **kwargs):
     if options.equal_weights:
         environment.events.init.add_listener(assign_equal_weights)
 
-    if options.headless and not options.host:
-        logger.error("The --host option is required when running in headless mode")
-        sys.exit(1)
-
-    if options.host and not (options.host.startswith("http://") or options.host.startswith("https://")):
+    if options.host and not (urlparse(options.host).scheme):
         logger.error(f"Invalid --host option: {options.host}. Did you mean https://{options.host}?")
         sys.exit(1)
 

Diff for: locust/test/test_main.py

@@ -1381,28 +1381,7 @@ def my_task(self):
             # ensure stats printer printed at least one report before shutting down and that there was a final report printed as well
             self.assertRegex(stderr, r".*Aggregated[\S\s]*Shutting down[\S\s]*Aggregated.*")
 
-    def test_headless_wo_host(self):
-        with mock_locustfile() as mocked:
-            proc = subprocess.Popen(
-                [
-                    "locust",
-                    "-f",
-                    mocked.file_path,
-                    "--run-time",
-                    "1s",
-                    "--headless",
-                    "--loglevel",
-                    "DEBUG",
-                ],
-                stdout=PIPE,
-                stderr=PIPE,
-                text=True,
-            )
-            stdout, stderr = proc.communicate(timeout=4)
-            self.assertIn("The --host option is required when running in headless mode", stderr)
-            self.assertEqual(1, proc.returncode)
-
-    def test_headless_wo_protocol(self):
+    def test_host_wo_protocol(self):
         with mock_locustfile() as mocked:
             proc = subprocess.Popen(
                 [