WebHost: Fix too-many-players error not showing (#4033)

* WebHost: fix 'too many players' error not showing

* WebHost, Tests: add basic tests for generate endpoint

* WebHost: hopefully make CodeQL happy with MAX_ROLL redirect

test/webhost/test_generate.py

@@ -0,0 +1,73 @@
+import zipfile
+from io import BytesIO
+
+from flask import url_for
+
+from . import TestBase
+
+
+class TestGenerate(TestBase):
+    def test_valid_yaml(self) -> None:
+        """
+        Verify that posting a valid yaml will start generating a game.
+        """
+        with self.app.app_context(), self.app.test_request_context():
+            yaml_data = """
+            name: Player1
+            game: Archipelago
+            Archipelago: {}
+            """
+            response = self.client.post(url_for("generate"),
+                                        data={"file": (BytesIO(yaml_data.encode("utf-8")), "test.yaml")},
+                                        follow_redirects=True)
+            self.assertEqual(response.status_code, 200)
+            self.assertTrue("/seed/" in response.request.path or
+                            "/wait/" in response.request.path,
+                            f"Response did not properly redirect ({response.request.path})")
+
+    def test_empty_zip(self) -> None:
+        """
+        Verify that posting an empty zip will give an error.
+        """
+        with self.app.app_context(), self.app.test_request_context():
+            zip_data = BytesIO()
+            zipfile.ZipFile(zip_data, "w").close()
+            zip_data.seek(0)
+            self.assertGreater(len(zip_data.read()), 0)
+            zip_data.seek(0)
+            response = self.client.post(url_for("generate"),
+                                        data={"file": (zip_data, "test.zip")},
+                                        follow_redirects=True)
+            self.assertIn("user-message", response.text,
+                          "Request did not call flash()")
+            self.assertIn("not find any valid files", response.text,
+                          "Response shows unexpected error")
+            self.assertIn("generate-game-form", response.text,
+                          "Response did not get user back to the form")
+
+    def test_too_many_players(self) -> None:
+        """
+        Verify that posting too many players will give an error.
+        """
+        max_roll = self.app.config["MAX_ROLL"]
+        # validate that max roll has a sensible value, otherwise we probably changed how it works
+        self.assertIsInstance(max_roll, int)
+        self.assertGreater(max_roll, 1)
+        self.assertLess(max_roll, 100)
+        # create a yaml with max_roll+1 players and watch it fail
+        with self.app.app_context(), self.app.test_request_context():
+            yaml_data = "---\n".join([
+                f"name: Player{n}\n"
+                "game: Archipelago\n"
+                "Archipelago: {}\n"
+                for n in range(1, max_roll + 2)
+            ])
+            response = self.client.post(url_for("generate"),
+                                        data={"file": (BytesIO(yaml_data.encode("utf-8")), "test.yaml")},
+                                        follow_redirects=True)
+            self.assertIn("user-message", response.text,
+                          "Request did not call flash()")
+            self.assertIn("limited to", response.text,
+                          "Response shows unexpected error")
+            self.assertIn("generate-game-form", response.text,
+                          "Response did not get user back to the form")