diff --git a/sanic/base.py b/sanic/base.py
index fd33838f..ff4833fa 100644
--- a/sanic/base.py
+++ b/sanic/base.py
@@ -36,7 +36,7 @@ class BaseSanic(
             warn(
                 f"{class_name} instance named '{name}' uses a format that is"
                 f"deprecated. Starting in version 21.12, {class_name} objects "
-                "be named only using alphanumeric characters, _, or -.",
+                "must be named only using alphanumeric characters, _, or -.",
                 DeprecationWarning,
             )
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 70d97573..65b218cf 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -15,6 +15,7 @@ from sanic.constants import HTTP_METHODS
 from sanic.router import Router
 
 
+slugify = re.compile(r"[^a-zA-Z0-9_\-]")
 random.seed("Pack my box with five dozen liquor jugs.")
 Sanic.test_mode = True
 
@@ -140,5 +141,5 @@ def url_param_generator():
 
 @pytest.fixture(scope="function")
 def app(request):
-    app = Sanic(request.node.name)
+    app = Sanic(slugify.sub("-", request.node.name))
     return app
diff --git a/tests/test_base.py b/tests/test_base.py
index 72567621..11d275a1 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -78,11 +78,25 @@ def test_names_okay(name):
     ),
 )
 def test_names_not_okay(name):
-    with pytest.warns(DeprecationWarning):
+    app_message = (
+        f"Sanic instance named '{name}' uses a format that isdeprecated. "
+        "Starting in version 21.12, Sanic objects must be named only using "
+        "alphanumeric characters, _, or -."
+    )
+    bp_message = (
+        f"Blueprint instance named '{name}' uses a format that isdeprecated. "
+        "Starting in version 21.12, Blueprint objects must be named only using "
+        "alphanumeric characters, _, or -."
+    )
+
+    with pytest.warns(DeprecationWarning) as app_e:
         app = Sanic(name)
 
-    with pytest.warns(DeprecationWarning):
+    with pytest.warns(DeprecationWarning) as bp_e:
         bp = Blueprint(name)
 
     assert app.name == name
     assert bp.name == name
+
+    assert app_e[0].message.args[0] == app_message
+    assert bp_e[0].message.args[0] == bp_message