101:  function getNextEntropy() public onlyAllowedCaller returns (uint256) { 
102:    require(currentSlotIndex <= maxSlotIndex, 'Max slot index reached.');
103:@>     uint256 entropy = getEntropy(currentSlotIndex, currentNumberIndex); 
104:
    ...
120:  }
diff --git a/test/EntropyGenerator.test.ts b/test/EntropyGenerator.test.ts
index 69551f5..f7e8698 100644
--- a/test/EntropyGenerator.test.ts
+++ b/test/EntropyGenerator.test.ts
@@ -3,7 +3,7 @@ import { ethers } from 'hardhat';
 import { EntropyGenerator } from '../typechain-types';
 import { HardhatEthersSigner } from '@nomicfoundation/hardhat-ethers/signers';
 
-describe('EntropyGenerator', function () {
+describe.only('EntropyGenerator', function () {
   let entropyGenerator: EntropyGenerator;
   let owner: HardhatEthersSigner;
   let allowedCaller: HardhatEthersSigner;
@@ -32,6 +32,15 @@ describe('EntropyGenerator', function () {
     expect(updatedCaller).to.equal(allowedCaller);
   });
 
+  it('getNextEntropy returns 0 entropy if entropySlots not properly init', async function () {
+    // call getNextEntropy when write entropy batches not finished
+    await expect(
+      entropyGenerator.connect(allowedCaller).getNextEntropy()
+    ).to.emit(entropyGenerator, 'EntropyRetrieved').withArgs(0);
+
+    // @audit: should revert getNextEntropy if entropySlots not properly init
+  });
+
   it('should write entropy batches 1', async function () {
     // Write entropy batch 1
     await entropyGenerator.writeEntropyBatch1();
  function getNextEntropy() public onlyAllowedCaller returns (uint256) {
...
+    require(currentSlotIndex < lastInitializedIndex, 'Slot not initialized');
    uint256 entropy = getEntropy(currentSlotIndex, currentNumberIndex);
