First attempt tests (#1)

tests/test_app.py

@@ -450,3 +450,79 @@ def test_custom_context():
     app = Sanic("custom", ctx=ctx)
 
     assert app.ctx == ctx
+
+
+def test_app_uvloop_config(caplog):
+    if uvloop_installed():
+        asyncio.set_event_loop_policy(None)
+        environ["SANIC_USE_UVLOOP"] = "false"
+
+        app = Sanic("dont_use_uvloop")
+
+        @app.get("/")
+        def _(request):
+            assert not isinstance(
+                asyncio.get_event_loop_policy(),
+                uvloop.EventLoopPolicy
+            )
+            return text("ok")
+
+        app.test_client.get("/")
+        del environ["SANIC_USE_UVLOOP"]
+
+        app = Sanic("use_uvloop")
+
+        @app.get("/")
+        async def _(request):
+            assert isinstance(
+                asyncio.get_event_loop_policy(),
+                uvloop.EventLoopPolicy
+            )
+            return text("ok")
+
+        app.test_client.get("/")
+
+        asyncio.set_event_loop_policy(None)
+
+        environ["SANIC_NO_UVLOOP"] = "true"
+        app = Sanic("use_uvloop_with_no_uvloop_set")
+
+        with caplog.at_level(logging.WARNING):
+            @app.get("/")
+            async def _(request):
+                assert isinstance(
+                    asyncio.get_event_loop_policy(),
+                    uvloop.EventLoopPolicy
+                )
+                return text("ok")
+
+            app.test_client.get("/")
+
+        del environ["SANIC_NO_UVLOOP"]
+        asyncio.set_event_loop_policy(None)
+
+        assert caplog.records[0].message == (
+            "You are running the app using uvloop, but the "
+            "'SANIC_NO_UVLOOP' environment variable (used to opt-out "
+            "of installing uvloop with Sanic) is set to true. If you "
+            "want to disable uvloop with Sanic, set the 'USE_UVLOOP' "
+            "configuration value to false."
+        )
+
+    elif not OS_IS_WINDOWS:
+        app = Sanic("wants_but_cant_use_uvloop")
+
+        with caplog.at_level(logging.WARNING):
+            @app.get("/")
+            async def _(request):
+                return text("ok")
+            app.test_client.get("/")
+
+        assert caplog.records[0].message == (
+            "You are trying to use uvloop, but uvloop is not "
+            "installed in your system. In order to use uvloop "
+            "you must first install it. Otherwise, you can disable "
+            "uvloop completely by setting the 'USE_UVLOOP' "
+            "configuration  value to false. The app will now continue "
+            "to run without using uvloop."
+        )