diff --git a/src/state.test.js b/src/state.test.js
index 4d5eda0..572cbc4 100644
--- a/src/state.test.js
+++ b/src/state.test.js
@@ -152,3 +152,69 @@ describe("createCombatState - multi player/enemy", () => {
     expect(state.enemies[0].instanceId).not.toBe(state.enemies[1].instanceId);
   });
 });
+
+describe("drawCards - indexed player", () => {
+  test("draws for player 1 leaving player 0 unchanged", () => {
+    const state = createCombatState(["ironclad", "ironclad"], ["jaw_worm"]);
+    const next = drawCards(state, 1, 3);
+    expect(next.players[0].hand).toHaveLength(0);
+    expect(next.players[1].hand).toHaveLength(3);
+    expect(next.players[1].drawPile).toHaveLength(7);
+  });
+
+  test("draws for player 0 explicitly", () => {
+    const state = createCombatState(["ironclad", "ironclad"], ["jaw_worm"]);
+    const next = drawCards(state, 0, 5);
+    expect(next.players[0].hand).toHaveLength(5);
+    expect(next.players[1].hand).toHaveLength(0);
+  });
+});
+
+describe("playCard - indexed player and enemy", () => {
+  test("player 1 plays a card targeting enemy 0", () => {
+    let state = createCombatState(["ironclad", "ironclad"], ["jaw_worm"]);
+    state = drawCards(state, 1, 5);
+    const cardIndex = state.players[1].hand.indexOf("strike_r");
+    const next = playCard(state, 1, cardIndex, 0);
+    expect(next.players[1].energy).toBe(2);
+    expect(next.players[1].hand).toHaveLength(4);
+    // player 0 unaffected
+    expect(next.players[0].energy).toBe(3);
+  });
+
+  test("playCard with player index returns null if not enough energy", () => {
+    let state = createCombatState(["ironclad", "ironclad"], ["jaw_worm"]);
+    state = drawCards(state, 1, 5);
+    const zeroEnergy = { ...state.players[1], energy: 0 };
+    state = {
+      ...state,
+      players: [state.players[0], zeroEnergy],
+    };
+    const cardIndex = state.players[1].hand.indexOf("strike_r");
+    const result = playCard(state, 1, cardIndex, 0);
+    expect(result).toBeNull();
+  });
+});
+
+describe("endTurn - indexed player", () => {
+  test("endTurn with playerIndex discards hand and marks player ready", () => {
+    let state = createCombatState(["ironclad", "ironclad"], ["jaw_worm"]);
+    state = drawCards(state, 0, 5);
+    const next = endTurn(state, 0);
+    expect(next.players[0].hand).toHaveLength(0);
+    expect(next.players[0].discardPile.length).toBeGreaterThan(0);
+    expect(next.combat.playersReady).toContain(0);
+    // phase stays player_turn until all players ready
+    expect(next.combat.phase).toBe("player_turn");
+  });
+
+  test("phase switches to enemy_turn when all players ready", () => {
+    let state = createCombatState(["ironclad", "ironclad"], ["jaw_worm"]);
+    state = drawCards(state, 0, 3);
+    state = drawCards(state, 1, 3);
+    state = endTurn(state, 0);
+    const next = endTurn(state, 1);
+    expect(next.combat.phase).toBe("enemy_turn");
+    expect(next.combat.playersReady).toHaveLength(2);
+  });
+});