Server isolation and detailed errors

Isolated the JsonServer to server.py inside protocols/json

Added specific errors for server startup timeout and server startup
failed

Refactored errors for Core to CoreError generic and refactored
StateError to CoreStateMismatchError derived from CoreError

test/common.py

@@ -0,0 +1,27 @@
+import socket
+
+
+def find_available_port(
+    preferred_port: int | None = None,
+    host: str = "127.0.0.1",
+) -> int:
+    """Return an available TCP port on the given host.
+
+    The preferred port is returned when available. Otherwise, the operating
+    system selects an available ephemeral port.
+    """
+    if preferred_port is not None:
+        if not 1 <= preferred_port <= 65535:
+            raise ValueError("preferred_port must be between 1 and 65535")
+
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+            try:
+                sock.bind((host, preferred_port))
+            except OSError:
+                pass
+            else:
+                return preferred_port
+
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+        sock.bind((host, 0))
+        return int(sock.getsockname()[1])

test/manual/core.py

@@ -0,0 +1,17 @@
+from time import sleep
+from dynalab_core import Core
+from dynalab_core.config import CoreConfig
+
+
+config = CoreConfig(port=8765)
+print(config)
+dl_core = Core(config)
+dl_core.start()
+print("started")
+
+try:
+    while True:
+        dl_core.wait(1)
+        print("waiting")
+except KeyboardInterrupt:
+    dl_core.stop()

test/manual/peer.py

@@ -0,0 +1,20 @@
+import asyncio
+
+
+async def main() -> None:
+    reader, writer = await asyncio.open_connection(
+        host="127.0.0.1",
+        port=8765,
+    )
+
+    print("Connected")
+
+    try:
+        await asyncio.sleep(10)
+    finally:
+        writer.close()
+        await writer.wait_closed()
+        print("Disconnected")
+
+
+asyncio.run(main())

test/test_core.py

@@ -0,0 +1,18 @@
+import pytest
+from dynalab_core import Core
+from dynalab_core.config import CoreConfig
+from dynalab_core.errors import CoreStateMismatchError
+from test.common import find_available_port
+
+
+def test_core_cannot_start_twice() -> None:
+    port = find_available_port(8765)
+    core = Core(CoreConfig(port=port))
+
+    core.start()
+
+    try:
+        with pytest.raises(CoreStateMismatchError):
+            core.start()
+    finally:
+        core.stop()

test/test_json_server.py

@@ -0,0 +1,34 @@
+import pytest
+from dynalab_core import Core
+from dynalab_core.config import CoreConfig
+from dynalab_core.errors import JsonServerStartupError, JsonServerTimeoutError
+from test.common import find_available_port
+
+
+def test_json_server_raises_timeout_error() -> None:
+    port = find_available_port(8765)
+    core = Core(CoreConfig(port=port))
+    core._json_server._debug_timeout_test = True
+    core._json_server._timeout = 0.01
+
+    try:
+        with pytest.raises(JsonServerTimeoutError):
+            core.start()
+    finally:
+        core.stop()
+
+
+def test_json_server_raises_startup_error() -> None:
+
+    port = find_available_port(8765)
+    core1 = Core(CoreConfig(port=port))
+    core2 = Core(CoreConfig(port=port))
+
+    core1.start()
+
+    try:
+        with pytest.raises(JsonServerStartupError):
+            core2.start()
+    finally:
+        core1.stop()
+        core2.stop()