add unit tests

tests/test_app_extensions.py

@@ -0,0 +1,48 @@
+from sanic import Sanic
+import pytest
+
+
+class MongoDB:
+
+    def __init__(self, name):
+        self.name = name
+
+
+class ClientSession:
+
+    def __init__(self, name):
+        self.name = name
+
+
+def test_app_extensions():
+    app = Sanic("test_app")
+    app["session"] = ClientSession("session")
+    app["db"] = MongoDB("mongo")
+    assert len(app) == 2
+    assert app["session"].name == "session"
+    assert app["db"].name == "mongo"
+
+
+def test_app_extensions_delete():
+    app = Sanic("test_app")
+    app["session"] = ClientSession("session")
+    assert len(app) == 1
+    del app["session"]
+    assert len(app) == 0
+
+
+def test_app_extensions_iteration():
+    app = Sanic("test_app")
+    app["session"] = ClientSession("session")
+    app["db"] = MongoDB("mongo")
+    count = 0
+    for extension in app:
+        count = count + 1
+    assert count == 2
+
+
+def test_app_equal():
+    app_1 = Sanic("test_app_1")
+    app_2 = Sanic("test_app_2")
+    assert (app_1 == app_2) == False
+    assert (app_1 == app_1) == True