feat: improve scouting dashboard and demo data

backend/scouting/tests/test_seed_demo_data.py

@@ -0,0 +1,33 @@
+import pytest
+from django.core.management import call_command
+
+from scouting.models import League, Player, PlayerSeasonStat
+
+
+@pytest.mark.django_db
+def test_seed_demo_data_creates_a_useful_scouting_board():
+    call_command("seed_demo_data")
+
+    assert Player.objects.count() >= 24
+    assert PlayerSeasonStat.objects.count() >= 24
+    assert set(League.objects.values_list("code", flat=True)) >= {
+        "LBA",
+        "ACB",
+        "ABA",
+        "BBL",
+        "BSL",
+        "LNB",
+        "ISBL",
+        "NBL",
+        "NZNBL",
+    }
+
+
+@pytest.mark.django_db
+def test_seed_demo_data_is_idempotent():
+    call_command("seed_demo_data")
+    first_count = Player.objects.count()
+
+    call_command("seed_demo_data")
+
+    assert Player.objects.count() == first_count