add server api handlers. Fix bug with cmd output

tests/test_server_api.py

@@ -0,0 +1,118 @@
+from fastapi.testclient import TestClient
+
+from nexus_sync.server import InMemoryStore, Store, create_app
+
+
+def _heartbeat_payload(client_id: str = "macbook-pro-01", result: dict | None = None) -> dict:
+    return {
+        "client_id": client_id,
+        "observed_at": "2026-05-24T13:20:30Z",
+        "client": {
+            "hostname": "macbook-pro.local",
+            "platform": "darwin",
+            "version": "0.1.0",
+        },
+        "state": {
+            "local_time": "2026-05-24T16:20:30+03:00",
+            "uptime_seconds": 1200,
+        },
+        "last_command_result": result,
+    }
+
+
+def _client(store: Store | None = None) -> TestClient:
+    app = create_app(
+        store=store or InMemoryStore(),
+        client_tokens={"macbook-pro-01": "client-token", "other-client": "other-token"},
+    )
+    return TestClient(app)
+
+
+def _send_heartbeat(client: TestClient, payload: dict | None = None):
+    return client.post(
+        "/api/v1/client/heartbeat",
+        json=payload or _heartbeat_payload(),
+        headers={"Authorization": "Bearer client-token"},
+    )
+
+
+def test_server_lists_clients_after_heartbeat() -> None:
+    store = InMemoryStore()
+    client = _client(store)
+    payload = _heartbeat_payload()
+    payload["available_commands"] = [
+        {"name": "hostname", "description": "Get hostname"},
+    ]
+    _send_heartbeat(client, payload)
+
+    response = client.get("/api/v1/server/clients")
+
+    assert response.status_code == 200
+    assert response.json()["clients"][0]["id"] == "macbook-pro-01"
+    assert response.json()["clients"][0]["available_commands"] == [
+        {"name": "hostname", "description": "Get hostname"},
+    ]
+
+
+def test_server_queues_command_for_client_and_heartbeat_delivers_it() -> None:
+    store = InMemoryStore()
+    client = _client(store)
+    _send_heartbeat(client)
+
+    created = client.post(
+        "/api/v1/server/clients/macbook-pro-01/commands",
+        json={"name": "hostname", "args": {}, "timeout_seconds": 30},
+    )
+
+    assert created.status_code == 201
+    command_id = created.json()["id"]
+    assert created.json()["client_id"] == "macbook-pro-01"
+    assert created.json()["status"] == "pending"
+
+    heartbeat = _send_heartbeat(client)
+
+    assert heartbeat.status_code == 200
+    assert heartbeat.json()["command"]["id"] == command_id
+    assert heartbeat.json()["command"]["name"] == "hostname"
+
+
+def test_server_rejects_command_for_unknown_client() -> None:
+    client = _client()
+
+    response = client.post(
+        "/api/v1/server/clients/missing-client/commands",
+        json={"name": "hostname", "args": {}, "timeout_seconds": 30},
+    )
+
+    assert response.status_code == 404
+
+
+def test_server_returns_command_with_result_after_client_reports_result() -> None:
+    store = InMemoryStore()
+    client = _client(store)
+    _send_heartbeat(client)
+    created = client.post(
+        "/api/v1/server/clients/macbook-pro-01/commands",
+        json={"name": "hostname", "args": {}, "timeout_seconds": 30},
+    )
+    command_id = created.json()["id"]
+    _send_heartbeat(client)
+
+    reported = _send_heartbeat(
+        client,
+        _heartbeat_payload(
+            result={
+                "command_id": command_id,
+                "status": "succeeded",
+                "return_code": 0,
+                "stdout": "host\n",
+                "stderr": "",
+            }
+        ),
+    )
+    fetched = client.get(f"/api/v1/server/commands/{command_id}")
+
+    assert reported.status_code == 200
+    assert fetched.status_code == 200
+    assert fetched.json()["status"] == "succeeded"
+    assert fetched.json()["result"]["stdout"] == "host\n"