feat(combat): summoning

tests/test_spells.py

@@ -108,13 +108,13 @@ def _make_engine(
 
 
 class TestSpellLoading:
-    """Given: data/spells/ directory with 10 JSON spell files
+    """Given: data/spells/ directory with 11 JSON spell files
     When: load_spell_registry is called
-    Then: all 10 spells are loaded with correct fields."""
+    Then: all 11 spells are loaded with correct fields."""
 
     def test_loads_all_10_spells(self) -> None:
         reg = load_spell_registry(_SPELLS_DIR)
-        assert len(reg) == 10
+        assert len(reg) == 11
 
     def test_spell_names_present(self) -> None:
         reg = load_spell_registry(_SPELLS_DIR)
@@ -122,6 +122,7 @@ class TestSpellLoading:
             "Magic Missile", "Burning Hands", "Fireball", "Lightning Bolt",
             "Cure Light Wounds", "Cure Moderate Wounds", "Hold Person",
             "Fear", "Bull's Strength", "Acid Arrow",
+            "Summon Monster II",
         }
         assert set(reg) == expected
 
@@ -411,3 +412,26 @@ class TestSpellDamageWithDr:
         engine._cast_spell(c, t, "Fireball")
         # Save fails (2), 6d6 rolls all 3 = 18 damage, DR 5/- -> 13 damage
         assert t.hp == hp_before - 13
+
+
+class TestSummonMonster:
+    """Given: a caster casting Summon Monster II
+    When: _cast_spell is called
+    Then: a celestial wolf is summoned adjacent to the caster."""
+
+    def test_summon_creature(self) -> None:
+        caster = _make_caster()
+        target = _make_target(hp_max=100)
+        engine, c, t = _make_engine(caster, target, [3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3])
+        hp_before = len(engine._states)
+        engine._cast_spell(c, t, "Summon Monster II")
+        # Caster + target + summoned = 3 combatants
+        assert len(engine._states) == hp_before + 1
+        # Find the summoned creature
+        summoned = [s for s in engine._states if s.combatant.id == "celestial_wolf"]
+        assert len(summoned) == 1
+        assert summoned[0].side == "players"
+        # Check it has correct HP
+        assert summoned[0].hp == 15
+        # Check transcript mentions summon
+        assert any("summon" in line.lower() for line in engine._transcript)