Implement and test claim reward method

src/UniStaker.sol

@@ -142,6 +142,16 @@ contract UniStaker is ReentrancyGuard {
     _stakeTokenSafeTransferFrom(address(surrogates[deposit.delegatee]), deposit.owner, _amount);
   }
 
+  function claimReward() external nonReentrant {
+    _updateReward(msg.sender);
+
+    uint256 _rewards = rewards[msg.sender];
+    if (_rewards == 0) return;
+    rewards[msg.sender] = 0;
+
+    SafeERC20.safeTransfer(REWARDS_TOKEN, msg.sender, _rewards);
+  }
+
   function notifyRewardsAmount(uint256 _amount) external {
     if (msg.sender != REWARDS_NOTIFIER) revert UniStaker__Unauthorized("not notifier", msg.sender);
     // TODO: It looks like the only thing we actually need to do here is update the

test/UniStaker.t.sol

@@ -1750,3 +1750,53 @@ contract Earned is UniStakerRewardsTest {
     assertLteWithinOnePercent(uniStaker.earned(_depositor2), _depositor2ExpectedEarnings);
   }
 }
+
+contract ClaimReward is UniStakerRewardsTest {
+  function testFuzz_SendsRewardsEarnedToTheUser(
+    address _depositor,
+    address _delegatee,
+    uint256 _stakeAmount,
+    uint256 _rewardAmount,
+    uint256 _durationPercent
+  ) public {
+    (_stakeAmount, _rewardAmount) = _boundToRealisticStakeAndReward(_stakeAmount, _rewardAmount);
+    _durationPercent = bound(_durationPercent, 0, 100);
+
+    // A user deposits staking tokens
+    _boundMintAndStake(_depositor, _stakeAmount, _delegatee);
+    // The contract is notified of a reward
+    _mintTransferAndNotifyReward(_rewardAmount);
+    // A portion of the duration passes
+    _jumpAheadByPercentOfRewardDuration(_durationPercent);
+
+    uint256 _earned = uniStaker.earned(_depositor);
+
+    vm.prank(_depositor);
+    uniStaker.claimReward();
+
+    assertEq(rewardToken.balanceOf(_depositor), _earned);
+  }
+
+  function testFuzz_ResetsTheRewardsEarnedByTheUser(
+    address _depositor,
+    address _delegatee,
+    uint256 _stakeAmount,
+    uint256 _rewardAmount,
+    uint256 _durationPercent
+  ) public {
+    (_stakeAmount, _rewardAmount) = _boundToRealisticStakeAndReward(_stakeAmount, _rewardAmount);
+    _durationPercent = bound(_durationPercent, 0, 100);
+
+    // A user deposits staking tokens
+    _boundMintAndStake(_depositor, _stakeAmount, _delegatee);
+    // The contract is notified of a reward
+    _mintTransferAndNotifyReward(_rewardAmount);
+    // A portion of the duration passes
+    _jumpAheadByPercentOfRewardDuration(_durationPercent);
+
+    vm.prank(_depositor);
+    uniStaker.claimReward();
+
+    assertEq(uniStaker.earned(_depositor), 0);
+  }
+}