test: add update_rewards strk pool flow (#46)

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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds a flow test for `update_rewards` with a STRK pool under consensus rewards and a `start_consensus_rewards` helper; updates flow ideas.
> 
> - **Tests**:
>   - Add `update_rewards_strk_pool_flow_test` in `src/flow_test/test.cairo` to validate staker rewards post-`update_rewards` and delegator rewards after next epoch under consensus STRK pool.
> - **Utilities**:
>   - Add `SystemState.start_consensus_rewards()` in `src/flow_test/utils.cairo` to set `consensus_rewards_first_epoch` and advance `K` epochs.
> - **Docs**:
>   - Update `src/flow_test/flow_ideas.md` by removing STRK-only pool case from `update_rewards` ideas.
> 
> <sup>Written by [Cursor Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit 5b22f3d. This will update automatically on new commits. Configure [here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: arad-starkware

src/flow_test/flow_ideas.md

@@ -3,7 +3,6 @@
 - Get staker info while staker has zero balance.
 
 ## `update_rewards`
-- staker with only strk pool.
 - staker with only btc pool.
 - staker with empty pool (STRK + BTC).
 - staker with 2 btc pools with different decimals.

src/flow_test/test.cairo

@@ -2888,3 +2888,47 @@ fn update_rewards_disable_rewards_consensus_rewards_flow_test() {
         :result, expected_error: StakingError::REWARDS_ALREADY_UPDATED.describe(),
     );
 }
+
+/// Flow:
+/// Start consensus rewards.
+/// Staker stake with STRK pool.
+/// Delegator delegate STRK.
+/// Advance K epochs.
+/// update_rewards.
+/// Test staker rewards.
+/// Test delegator rewards.
+/// Advance epoch.
+/// Test delegator rewards.
+#[test]
+fn update_rewards_strk_pool_flow_test() {
+    let cfg: StakingInitConfig = Default::default();
+    let mut system = SystemConfigTrait::basic_stake_flow_cfg(:cfg).deploy();
+    system.start_consensus_rewards();
+    let stake_amount = system.staking.get_min_stake();
+    let delegation_amount = STRK_CONFIG.min_for_rewards;
+    let staker = system.new_staker(amount: stake_amount);
+    let commission = 200;
+    system.stake(:staker, amount: stake_amount, pool_enabled: true, :commission);
+    let pool = system.staking.get_pool(:staker);
+    let delegator = system.new_delegator(amount: delegation_amount);
+    system.delegate(:delegator, :pool, amount: delegation_amount);
+    system.advance_k_epochs();
+
+    system.update_rewards(:staker, disable_rewards: false);
+    let (expected_staker_rewards, expected_pool_rewards) =
+        calculate_staker_strk_rewards_with_balances_v3(
+        amount_own: stake_amount,
+        pool_amount: delegation_amount,
+        :commission,
+        staking_contract: system.staking.address,
+        minting_curve_contract: system.minting_curve.address,
+    );
+    let staker_rewards = system.staker_claim_rewards(:staker);
+    let delegator_rewards = system.delegator_claim_rewards(:delegator, :pool);
+    assert!(staker_rewards == expected_staker_rewards);
+    assert!(delegator_rewards.is_zero());
+
+    system.advance_epoch();
+    let delegator_rewards = system.delegator_claim_rewards(:delegator, :pool);
+    assert!(delegator_rewards == expected_pool_rewards);
+}

src/flow_test/utils.cairo

@@ -1263,6 +1263,12 @@ pub(crate) impl SystemImpl of SystemTrait {
             .deploy_btc_token(:decimals);
         btc_token
     }
+
+    fn start_consensus_rewards(self: SystemState) {
+        let epoch_id = self.staking.get_current_epoch() + K.into();
+        self.staking.set_consensus_rewards_first_epoch(:epoch_id);
+        self.advance_k_epochs();
+    }
 }
 
 #[generate_trait]