test(campaigns): promote cookie-safe request helper to shared conftest fixture

Moves the local _post cookie-clearing helper into a shared 'api' fixture
in conftest.py so later router tests in this plan (Tasks 10/11) don't
have to reinvent or forget the TestClient cookie-vs-Authorization-header
gotcha. Also adds a one-line comment at both require_any_role("manager")
call sites clarifying admin passthrough is automatic.

backend/app/routers/campaigns.py

@@ -446,6 +446,7 @@ def approve_campaign_endpoint(
     campaign_id: str,
     payload: ApprovePayload,
     db: Session = Depends(get_db),
+    # admin passes automatically via require_any_role's built-in bypass — do not add "admin" here
     current_user: User = Depends(require_any_role("manager")),
 ) -> dict:
     """Manager approves a pending campaign, fixing its start date and activating it."""
@@ -477,6 +478,7 @@ def reject_campaign_endpoint(
     campaign_id: str,
     payload: RejectPayload,
     db: Session = Depends(get_db),
+    # admin passes automatically via require_any_role's built-in bypass — do not add "admin" here
     current_user: User = Depends(require_any_role("manager")),
 ) -> dict:
     """Manager rejects a pending campaign, returning it to draft with a reason."""

backend/tests/conftest.py

@@ -328,3 +328,25 @@ def manager_token(client, manager_user):
 def manager_headers(manager_token):
     """Return authorization headers for manager user."""
     return {"Authorization": f"Bearer {manager_token}"}
+
+
+@pytest.fixture(scope="function")
+def api(client):
+    """Issue an authenticated request while avoiding stale-cookie role bleed.
+
+    ``client``'s cookie jar persists across requests within a test, and
+    ``get_current_user`` prefers the ``aegis_token`` cookie over the
+    ``Authorization`` header. A test that uses more than one role's
+    ``*_headers`` fixture (e.g. submit as red_lead, then approve as
+    manager) would otherwise have its *first* request silently
+    authenticate as whichever role's fixture happens to log in last,
+    since pytest resolves all fixtures before the test body runs. Use
+    this instead of ``client.post``/``client.get`` directly whenever a
+    test mixes more than one role.
+
+    Usage: ``api("post", url, headers, json=payload)``.
+    """
+    def _request(method: str, url: str, headers: dict, **kwargs):
+        client.cookies.clear()
+        return getattr(client, method)(url, headers=headers, **kwargs)
+    return _request

backend/tests/test_campaign_approval_router.py

@@ -6,20 +6,6 @@ from app.models.test import Test
 from app.models.enums import TestState
 
 
-def _post(client, url, headers, **kwargs):
-    """POST while forcing auth via the Authorization header.
-
-    The login endpoint also sets an HttpOnly ``aegis_token`` cookie, and the
-    shared ``TestClient`` cookie jar persists across requests within a test.
-    ``get_current_user`` prefers the cookie over the ``Authorization``
-    header, so once a second role's headers fixture logs in (setting its own
-    cookie), a request made with an *earlier* role's headers would silently
-    authenticate as the later role unless the leftover cookie is cleared.
-    """
-    client.cookies.clear()
-    return client.post(url, headers=headers, **kwargs)
-
-
 def _make_draft_campaign(db, owner_id):
     tech = Technique(mitre_id="T1059", name="Command Line", tactic="execution", platforms=["windows"])
     db.add(tech)
@@ -36,25 +22,25 @@ def _make_draft_campaign(db, owner_id):
     return campaign
 
 
-def test_lead_can_submit_own_campaign(client, db, red_lead_user, red_lead_headers):
+def test_lead_can_submit_own_campaign(api, db, red_lead_user, red_lead_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    resp = _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
+    resp = api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
     assert resp.status_code == 200
     assert resp.json()["status"] == "pending_approval"
 
 
-def test_red_tech_cannot_submit(client, db, red_lead_user, red_tech_headers):
+def test_red_tech_cannot_submit(api, db, red_lead_user, red_tech_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    resp = _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_tech_headers)
+    resp = api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_tech_headers)
     assert resp.status_code == 403
 
 
-def test_manager_can_approve_and_sets_start_date(client, db, red_lead_user, red_lead_headers, manager_headers):
+def test_manager_can_approve_and_sets_start_date(api, db, red_lead_user, red_lead_headers, manager_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
+    api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
 
-    resp = _post(
-        client,
+    resp = api(
+        "post",
         f"/api/v1/campaigns/{campaign.id}/approve",
         manager_headers,
         json={"start_date": "2026-09-01T00:00:00"},
@@ -65,12 +51,12 @@ def test_manager_can_approve_and_sets_start_date(client, db, red_lead_user, red_
     assert body["start_date"] is not None
 
 
-def test_lead_cannot_approve(client, db, red_lead_user, red_lead_headers):
+def test_lead_cannot_approve(api, db, red_lead_user, red_lead_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
+    api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
 
-    resp = _post(
-        client,
+    resp = api(
+        "post",
         f"/api/v1/campaigns/{campaign.id}/approve",
         red_lead_headers,
         json={"start_date": "2026-09-01T00:00:00"},
@@ -78,12 +64,12 @@ def test_lead_cannot_approve(client, db, red_lead_user, red_lead_headers):
     assert resp.status_code == 403
 
 
-def test_admin_can_approve_as_manager_backup(client, db, red_lead_user, red_lead_headers, auth_headers):
+def test_admin_can_approve_as_manager_backup(api, db, red_lead_user, red_lead_headers, auth_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
+    api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
 
-    resp = _post(
-        client,
+    resp = api(
+        "post",
         f"/api/v1/campaigns/{campaign.id}/approve",
         auth_headers,
         json={"start_date": "2026-09-01T00:00:00"},
@@ -91,12 +77,12 @@ def test_admin_can_approve_as_manager_backup(client, db, red_lead_user, red_lead
     assert resp.status_code == 200
 
 
-def test_manager_can_reject_with_reason(client, db, red_lead_user, red_lead_headers, manager_headers):
+def test_manager_can_reject_with_reason(api, db, red_lead_user, red_lead_headers, manager_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
+    api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
 
-    resp = _post(
-        client,
+    resp = api(
+        "post",
         f"/api/v1/campaigns/{campaign.id}/reject",
         manager_headers,
         json={"reason": "Needs more detail"},
@@ -105,12 +91,12 @@ def test_manager_can_reject_with_reason(client, db, red_lead_user, red_lead_head
     assert resp.json()["status"] == "draft"
 
 
-def test_manager_reject_without_reason_rejected_by_validation(client, db, red_lead_user, red_lead_headers, manager_headers):
+def test_manager_reject_without_reason_rejected_by_validation(api, db, red_lead_user, red_lead_headers, manager_headers):
     campaign = _make_draft_campaign(db, red_lead_user.id)
-    _post(client, f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
+    api("post", f"/api/v1/campaigns/{campaign.id}/submit", red_lead_headers)
 
-    resp = _post(
-        client,
+    resp = api(
+        "post",
         f"/api/v1/campaigns/{campaign.id}/reject",
         manager_headers,
         json={"reason": ""},