Fix hint loading for admins with /api/v1/hints/<id>?preview=true (#786)

* Fix hint loading for admins by adding /api/v1/hints/<id>?preview=true for use by admins
* Add tests for admin Hint preview

tests/api/v1/test_hints.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
+from CTFd.models import Hints
 from tests.helpers import *
 
 
@@ -11,6 +12,7 @@ def test_api_hint_get_non_admin():
         with login_as_user(app) as client:
             r = client.get('/api/v1/hints', json="")
             assert r.status_code == 403
+            assert Hints.query.count() == 0
     destroy_ctfd(app)
 
 
@@ -45,4 +47,44 @@ def test_api_hint_post_admin():
                 "cost": "1",
                 "challenge": 1})
             assert r.status_code == 200
+            assert Hints.query.count() == 1
+    destroy_ctfd(app)
+
+
+def test_admins_can_preview_hints():
+    """Test that admins are able to bypass restrictions and preview hints with ?preview=true"""
+    app = create_ctfd()
+    with app.app_context():
+        gen_challenge(app.db)
+        gen_hint(app.db, challenge_id=1, cost=100)
+        client = login_as_user(app, name="admin", password="password")
+        r = client.get('/api/v1/hints/1')
+        assert r.status_code == 200
+        hint = r.get_json()
+        assert hint.get('content') is None
+
+        r = client.get('/api/v1/hints/1?preview=true')
+        assert r.status_code == 200
+        hint = r.get_json()
+        assert hint['data']['content'] == "This is a hint"
+    destroy_ctfd(app)
+
+
+def test_users_cannot_preview_hints():
+    """Test that users aren't able to preview hints"""
+    app = create_ctfd()
+    with app.app_context():
+        gen_challenge(app.db)
+        gen_hint(app.db, challenge_id=1, cost=100)
+        register_user(app)
+        client = login_as_user(app)
+        r = client.get('/api/v1/hints/1')
+        assert r.status_code == 200
+        hint = r.get_json()
+        assert hint.get('content') is None
+
+        r = client.get('/api/v1/hints/1?preview=true')
+        assert r.status_code == 200
+        hint = r.get_json()
+        assert hint['data'].get('content') is None
     destroy_ctfd(app)