fix(generic): Migrate ServerContainer from deprecated decorator to HttpWaitStrategy (#971)

Hi there, I've seen this deprecation warning in a generic container.
This is my first PR in this project; I'm open to any feedback you may
have!

Related:
#874

Also updates the docs, highlighted in [this
comment](#874 (comment))

Co-authored-by: Jon Miller <jonmiller@netflix.com>
Co-authored-by: Roy Moore <roy@moore.co.il>

Author: 3 people

docs/features/wait_strategies.md

@@ -4,19 +4,17 @@ Testcontainers-Python provides several strategies to wait for containers to be r
 
 ## Basic Wait Strategy
 
-The simplest way to wait for a container is using the `wait_container_is_ready` decorator:
+The simplest way to wait for a container is using a structured wait strategy:
 
 ```python
-from testcontainers.core.waiting_utils import wait_container_is_ready
+from testcontainers.core.wait_strategies import HttpWaitStrategy
 
 class MyContainer(DockerContainer):
-    @wait_container_is_ready()
     def _connect(self):
-        # Your connection logic here
-        pass
+        HttpWaitStrategy(8080).wait_until_ready(self)
 ```
 
-This decorator will retry the method until it succeeds or times out. By default, it will retry for 120 seconds with a 1-second interval between attempts.
+The strategy will retry until it succeeds or times out. By default, it will retry for 120 seconds with a 1-second interval between attempts.
 
 ## Log-based Waiting
 

modules/generic/testcontainers/generic/server.py

@@ -1,13 +1,11 @@
 from typing import Union
-from urllib.error import HTTPError, URLError
-from urllib.request import urlopen
 
 import httpx
 
 from testcontainers.core.container import DockerContainer
 from testcontainers.core.exceptions import ContainerStartException
 from testcontainers.core.image import DockerImage
-from testcontainers.core.waiting_utils import wait_container_is_ready
+from testcontainers.core.wait_strategies import HttpWaitStrategy
 
 
 class ServerContainer(DockerContainer):
@@ -40,19 +38,9 @@ def __init__(self, port: int, image: Union[str, DockerImage]) -> None:
         self.internal_port = port
         self.with_exposed_ports(self.internal_port)
 
-    @wait_container_is_ready(HTTPError, URLError)
     def _connect(self) -> None:
-        # noinspection HttpUrlsUsage
-        url = self._create_connection_url()
-        try:
-            with urlopen(url) as r:
-                assert b"" in r.read()
-        except HTTPError as e:
-            # 404 is expected, as the server may not have the specific endpoint we are looking for
-            if e.code == 404:
-                pass
-            else:
-                raise
+        strategy = HttpWaitStrategy(self.internal_port).for_status_code(404)
+        strategy.wait_until_ready(self)
 
     def get_api_url(self) -> str:
         raise NotImplementedError