reworked the RNG to use a deterministic seed

tests/forge/FenwickTree.t.sol

@@ -110,10 +110,10 @@ contract FenwickTreeTest is DSTestPlus {
         uint256 insertions_,
         uint256 totalAmount_,
         uint256 scaleIndex_,
-        uint256 factor_
-        ) external {
-
-        _tree.fuzzyFill(insertions_, totalAmount_, false);
+        uint256 factor_,
+        uint256 seed_
+    ) external {
+        _tree.fuzzyFill(insertions_, totalAmount_, seed_, false);
 
         uint256 scaleIndex = bound(scaleIndex_, 2, MAX_INDEX);
         uint256 subIndex   = randomInRange(1, scaleIndex - 1);
@@ -159,10 +159,10 @@ contract FenwickTreeTest is DSTestPlus {
         uint256 insertions_,
         uint256 totalAmount_,
         uint256 scaleIndex_,
-        uint256 factor_
-        ) external {
-
-        _tree.fuzzyFill(insertions_, totalAmount_, false);
+        uint256 factor_,
+        uint256 seed_
+    ) external {
+        _tree.fuzzyFill(insertions_, totalAmount_, seed_, false);
 
         uint256 scaleIndex = bound(scaleIndex_, 2, 7388);
         uint256 subIndex = randomInRange(0, scaleIndex - 1);
@@ -191,10 +191,10 @@ contract FenwickTreeTest is DSTestPlus {
     // TODO: check random parent to verify sum post removal
     function testLoadFenwickFuzzyRemoval(
         uint256 insertions_,
-        uint256 totalAmount_
-        ) external {
-
-        _tree.fuzzyFill(insertions_, totalAmount_, true);
+        uint256 totalAmount_,
+        uint256 seed_
+    ) external {
+        _tree.fuzzyFill(insertions_, totalAmount_, seed_, true);
 
         uint256 removalIndex = _tree.getIByInsertIndex(randomInRange(0, _tree.numInserts() - 1));
         uint256 removalAmount = _tree.get(removalIndex); 
@@ -208,7 +208,6 @@ contract FenwickTreeTest is DSTestPlus {
         assertEq(preRemovalIndexSum - removalAmount, postRemovalIndexSum);
         assertEq(preRemovalTreeSum - removalAmount, _tree.treeSum());
     }
-
 }
 
 contract FenwickTreeGasLoadTest is DSTestPlus {

tests/forge/Heap.t.sol

@@ -231,10 +231,10 @@ contract HeapTest is DSTestPlus {
         assertEq(_loans.getTotalTps(),    7);
     }
 
-    function testLoadHeapFuzzy(uint256 inserts_) public {
+    function testLoadHeapFuzzy(uint256 inserts_, uint256 seed_) public {
 
         // test adding different TPs
-        _loans.fuzzyFill(inserts_, true);
+        _loans.fuzzyFill(inserts_, seed_, true);
 
         // test adding different TPs
         address removeAddress = _loans.getIdByInsertIndex(randomInRange(1, _loans.numInserts() - 1, true));

tests/forge/utils/DSTestPlus.sol

@@ -22,7 +22,7 @@ abstract contract DSTestPlus is Test, IPoolEvents {
     using EnumerableSet for EnumerableSet.UintSet;
 
     // nonce for generating random addresses
-    uint16 internal _nonce = 0;
+    uint256 internal _nonce = 0;
 
     // mainnet address of AJNA token, because tests are forked
     address internal _ajna = 0x9a96ec9B57Fb64FbC60B423d1f4da7691Bd35079;
@@ -1251,30 +1251,34 @@ abstract contract DSTestPlus is Test, IPoolEvents {
         lup_ = _priceAt(lupIndex); 
     }
 
+    function setRandomSeed(uint256 seed) public {
+        _nonce = seed;
+    }
+
+    function getNextNonce() public returns (uint256) {
+        return _nonce == type(uint256).max ? 0 : ++_nonce;
+    }
+
     function randomInRange(uint256 min, uint256 max) public returns (uint256) {
         return randomInRange(min, max, false);
     }
 
     function randomInRange(uint256 min, uint256 max, bool nonZero) public returns (uint256) {
         if      (max == 0 && nonZero) return 1;
         else if (max == min)           return max;
-        uint256 rand = uint(keccak256(abi.encodePacked(block.timestamp, msg.sender, _nonce))) % (max - min + 1) + min;
-        _nonce++;
-        return rand;
+        return uint(keccak256(abi.encodePacked(msg.sender, getNextNonce()))) % (max - min + 1) + min;
     }
 
     // returns a random index between 1 and 7388
     function _randomIndex() internal returns (uint256 index_) {
         // calculate a random index between 1 and 7388
-        index_ = 1 + uint256(keccak256(abi.encodePacked(block.number, block.difficulty))) % 7387;
-        vm.roll(block.number + 1); // advance block to ensure that the index price is different
+        index_ = 1 + uint256(keccak256(abi.encodePacked(msg.sender, getNextNonce()))) % 7387;
     }
 
     // returns a random index between 1 and a given maximum
     // used for testing in NFT pools where higher indexes (and lower prices) would require so many NFTs that gas and memory limits would be exceeded
     function _randomIndexWithMinimumPrice(uint256 minimumPrice_) internal returns (uint256 index_) {
-        index_ = 1 + uint256(keccak256(abi.encodePacked(block.number, block.difficulty))) % minimumPrice_;
-        vm.roll(block.number + 1); // advance block to ensure that the index price is different
+        index_ = 1 + uint256(keccak256(abi.encodePacked(msg.sender, getNextNonce()))) % minimumPrice_;
     }
 
     // find the bucket index in array corresponding to the highest bucket price

tests/forge/utils/FenwickTreeInstance.sol

@@ -68,11 +68,11 @@ contract FenwickTreeInstance is DSTestPlus {
      *  @notice fills fenwick tree with fuzzed values and tests additions.
      */
     function fuzzyFill(
-        uint256 insertions_,
-        uint256 amount_,
-        bool trackInserts)
-        external {
-
+        uint256 insertions_,    // number of insertions to perform
+        uint256 amount_,        // total amount to insert
+        uint256 seed_,          // seed for psuedorandom number generator
+        bool    trackInserts
+    ) external {
         uint256 i;
         uint256 amount;
 
@@ -83,6 +83,8 @@ contract FenwickTreeInstance is DSTestPlus {
         uint256 totalAmount = bound(amount_, 1 * 1e18, 9_000_000_000_000_000 * 1e18);
         uint256 totalAmountDec = totalAmount;
 
+        // Initialize and print seed for randomness
+        setRandomSeed(bound(seed_, 0, type(uint256).max - 1));
 
         while (totalAmountDec > 0 && insertsDec > 0) {
 
@@ -106,4 +108,3 @@ contract FenwickTreeInstance is DSTestPlus {
         assertEq(deposits.treeSum(), totalAmount);
     }
 }
-

tests/forge/utils/HeapInstance.sol

@@ -60,17 +60,20 @@ contract HeapInstance is DSTestPlus {
      *  @notice fills Heap with fuzzed values and tests additions.
      */
     function fuzzyFill(
-        uint256 inserts_,
-        bool trackInserts_)
-        external {
-
+        uint256 inserts_,       // number of insertions to perform
+        uint256 seed_,          // seed for psuedorandom number generator
+        bool trackInserts_
+    ) external {
         uint256 tp;
         address borrower;
 
         // Calculate total insertions 
         uint256 totalInserts = bound(inserts_, 1000, 2000);
         uint256 insertsDec = totalInserts;
 
+        // Initialize and print seed for randomness
+        setRandomSeed(bound(seed_, 0, type(uint256).max - 1));
+
         while (insertsDec > 0) {
 
             // build address and TP
@@ -91,4 +94,3 @@ contract HeapInstance is DSTestPlus {
         assertEq(_heap.loans.length - 1, totalInserts);
     }
 }
-