test: cover Copilot enterprise overrides

Maintainer edit: add mocked coverage for the enterprise endpoint and client ID override paths, and document the environment variables users must set before OAuth login.

docs/configuration.md

@@ -677,6 +677,16 @@ nanobot agent -c ~/.nanobot-telegram/config.json -w /tmp/nanobot-telegram-test -
 
 GitHub Copilot uses OAuth instead of API keys. Requires a [GitHub account with a plan](https://github.com/features/copilot/plans) configured. No `providers.githubCopilot` block is needed in `config.json`; `nanobot provider login` stores the OAuth session outside config.
 
+For GitHub Enterprise / Copilot for Business, set the endpoint overrides you need before login:
+```bash
+export NANOBOT_GITHUB_COPILOT_CLIENT_ID="your-enterprise-client-id"
+export NANOBOT_GITHUB_DEVICE_CODE_URL="https://ghe.example/login/device/code"
+export NANOBOT_GITHUB_ACCESS_TOKEN_URL="https://ghe.example/login/oauth/access_token"
+export NANOBOT_GITHUB_USER_URL="https://api.ghe.example/user"
+export NANOBOT_COPILOT_TOKEN_URL="https://api.ghe.example/copilot_internal/v2/token"
+export NANOBOT_COPILOT_BASE_URL="https://copilot-api.ghe.example"
+```
+
 **1. Login:**
 ```bash
 nanobot provider login github-copilot

tests/providers/test_github_copilot_enterprise.py

@@ -2,6 +2,10 @@
 
 from __future__ import annotations
 
+from types import SimpleNamespace
+
+import pytest
+
 from nanobot.providers import github_copilot_provider as gc
 
 
@@ -30,3 +34,110 @@ def test_provider_api_base_honors_env_override(monkeypatch):
     monkeypatch.setenv("NANOBOT_COPILOT_BASE_URL", "https://copilot-api.acme.ghe.com")
     provider = gc.GitHubCopilotProvider()
     assert provider.api_base == "https://copilot-api.acme.ghe.com"
+
+
+def test_login_uses_enterprise_endpoint_overrides(monkeypatch):
+    monkeypatch.setenv("NANOBOT_GITHUB_COPILOT_CLIENT_ID", "enterprise-client-id")
+    monkeypatch.setenv("NANOBOT_GITHUB_DEVICE_CODE_URL", "https://ghe.example/login/device/code")
+    monkeypatch.setenv(
+        "NANOBOT_GITHUB_ACCESS_TOKEN_URL",
+        "https://ghe.example/login/oauth/access_token",
+    )
+    monkeypatch.setenv("NANOBOT_GITHUB_USER_URL", "https://api.ghe.example/user")
+    monkeypatch.setattr(gc.webbrowser, "open", lambda _url: None)
+
+    calls = []
+    saved = []
+
+    class FakeResponse:
+        def __init__(self, payload):
+            self._payload = payload
+
+        def raise_for_status(self):
+            pass
+
+        def json(self):
+            return self._payload
+
+    class FakeClient:
+        def __init__(self, *args, **kwargs):
+            pass
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, *args):
+            return False
+
+        def post(self, url, *, headers, data):
+            calls.append(("post", url, data))
+            if url.endswith("/device/code"):
+                return FakeResponse(
+                    {
+                        "device_code": "device-code",
+                        "user_code": "user-code",
+                        "verification_uri": "https://ghe.example/device",
+                        "interval": 1,
+                        "expires_in": 60,
+                    }
+                )
+            return FakeResponse({"access_token": "github-token", "expires_in": 3600})
+
+        def get(self, url, *, headers):
+            calls.append(("get", url, headers))
+            return FakeResponse({"login": "enterprise-user"})
+
+    monkeypatch.setattr(gc.httpx, "Client", FakeClient)
+    monkeypatch.setattr(gc, "get_storage", lambda: SimpleNamespace(save=saved.append))
+
+    token = gc.login_github_copilot(print_fn=lambda _message: None)
+
+    assert token.access == "github-token"
+    assert saved[0].account_id == "enterprise-user"
+    assert calls[0] == (
+        "post",
+        "https://ghe.example/login/device/code",
+        {"client_id": "enterprise-client-id", "scope": gc.GITHUB_COPILOT_SCOPE},
+    )
+    assert calls[1][0:2] == ("post", "https://ghe.example/login/oauth/access_token")
+    assert calls[1][2]["client_id"] == "enterprise-client-id"
+    assert calls[2][0:2] == ("get", "https://api.ghe.example/user")
+
+
+@pytest.mark.asyncio
+async def test_copilot_token_exchange_uses_enterprise_endpoint_override(monkeypatch):
+    monkeypatch.setenv(
+        "NANOBOT_COPILOT_TOKEN_URL",
+        "https://api.ghe.example/copilot_internal/v2/token",
+    )
+    monkeypatch.setattr(gc, "_load_github_token", lambda: SimpleNamespace(access="github-token"))
+
+    calls = []
+
+    class FakeResponse:
+        def raise_for_status(self):
+            pass
+
+        def json(self):
+            return {"token": "copilot-token", "refresh_in": 120}
+
+    class FakeAsyncClient:
+        def __init__(self, *args, **kwargs):
+            pass
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *args):
+            return False
+
+        async def get(self, url, *, headers):
+            calls.append((url, headers))
+            return FakeResponse()
+
+    monkeypatch.setattr(gc.httpx, "AsyncClient", FakeAsyncClient)
+
+    provider = gc.GitHubCopilotProvider()
+
+    assert await provider._get_copilot_access_token() == "copilot-token"
+    assert calls[0][0] == "https://api.ghe.example/copilot_internal/v2/token"