test: add Utils contract

test: move resetPrank in Utils
test: remove unneeded vm in BaseHandler
test: use only resetPrank function to change caller

test/Base.t.sol

@@ -12,13 +12,14 @@ import { ERC20MissingReturn } from "./mocks/ERC20MissingReturn.sol";
 import { Assertions } from "./utils/Assertions.sol";
 import { Events } from "./utils/Events.sol";
 import { Modifiers } from "./utils/Modifiers.sol";
+import { Utils } from "./utils/Utils.sol";
 
 struct Users {
     address sender;
     address recipient;
 }
 
-abstract contract Base_Test is Assertions, Events, Modifiers, Test {
+abstract contract Base_Test is Assertions, Events, Modifiers, Test, Utils {
     using SafeCast for uint256;
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -64,11 +65,9 @@ abstract contract Base_Test is Assertions, Events, Modifiers, Test {
         users.sender = createUser("sender");
         users.recipient = createUser("recipient");
 
-        vm.label(address(openEnded), "Open Ended");
-        vm.label(address(dai), "DAI");
-        vm.label(address(usdt), "USDT");
+        labelConctracts();
 
-        vm.startPrank({ msgSender: users.sender });
+        resetPrank(users.sender);
     }
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -86,6 +85,12 @@ abstract contract Base_Test is Assertions, Events, Modifiers, Test {
         return user;
     }
 
+    function labelConctracts() internal {
+        vm.label(address(openEnded), "Open Ended");
+        vm.label(address(dai), "DAI");
+        vm.label(address(usdt), "USDT");
+    }
+
     function normalizeBalance(uint256 streamId) internal view returns (uint256) {
         return normalizeTransferAmount(streamId, openEnded.getBalance(streamId));
     }
@@ -138,10 +143,4 @@ abstract contract Base_Test is Assertions, Events, Modifiers, Test {
     function expectCallToTransferFrom(IERC20 asset, address from, address to, uint256 amount) internal {
         vm.expectCall({ callee: address(asset), data: abi.encodeCall(IERC20.transferFrom, (from, to, amount)) });
     }
-
-    /// @dev Stops the active prank and sets a new one.
-    function resetPrank(address msgSender) internal {
-        vm.stopPrank();
-        vm.startPrank(msgSender);
-    }
 }

test/invariant/handlers/BaseHandler.sol

@@ -2,24 +2,20 @@
 pragma solidity >=0.8.22 <0.9.0;
 
 import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
-import { Vm } from "forge-std/src/Vm.sol";
 import { StdCheats } from "forge-std/src/StdCheats.sol";
-import { StdUtils } from "forge-std/src/StdUtils.sol";
 
+import { Utils } from "../../utils/Utils.sol";
 import { TimestampStore } from "../stores/TimestampStore.sol";
 
 /// @notice Base contract with common logic needed by all handler contracts.
-abstract contract BaseHandler is StdCheats, StdUtils {
+abstract contract BaseHandler is StdCheats, Utils {
     /*//////////////////////////////////////////////////////////////////////////
                                      CONSTANTS
     //////////////////////////////////////////////////////////////////////////*/
 
     /// @dev Maximum number of streams that can be created during an invariant campaign.
     uint256 internal constant MAX_STREAM_COUNT = 100;
 
-    /// @dev The virtual address of the Foundry VM.
-    address internal constant VM_ADDRESS = address(uint160(uint256(keccak256("hevm cheat code"))));
-
     /*//////////////////////////////////////////////////////////////////////////
                                      VARIABLES
     //////////////////////////////////////////////////////////////////////////*/
@@ -40,9 +36,6 @@ abstract contract BaseHandler is StdCheats, StdUtils {
     /// @dev Reference to the timestamp store, which is needed for simulating the passage of time.
     TimestampStore public timestampStore;
 
-    /// @dev An instance of the Foundry VM, which contains cheatcodes for testing.
-    Vm internal constant vm = Vm(VM_ADDRESS);
-
     /*//////////////////////////////////////////////////////////////////////////
                                     CONSTRUCTOR
     //////////////////////////////////////////////////////////////////////////*/
@@ -90,8 +83,7 @@ abstract contract BaseHandler is StdCheats, StdUtils {
 
     /// @dev Makes the provided sender the caller.
     modifier useNewSender(address sender) {
-        vm.startPrank(sender);
+        resetPrank(sender);
         _;
-        vm.stopPrank();
     }
 }

test/invariant/handlers/OpenEndedHandler.sol

@@ -60,17 +60,15 @@ contract OpenEndedHandler is BaseHandler {
     modifier useFuzzedStreamRecipient() {
         uint256 lastStreamId = openEndedStore.lastStreamId();
         currentRecipient = openEndedStore.recipients(currentStreamId);
-        vm.startPrank(currentRecipient);
+        resetPrank(currentRecipient);
         _;
-        vm.stopPrank();
     }
 
     modifier useFuzzedStreamSender() {
         uint256 lastStreamId = openEndedStore.lastStreamId();
         currentSender = openEndedStore.senders(currentStreamId);
-        vm.startPrank(currentSender);
+        resetPrank(currentSender);
         _;
-        vm.stopPrank();
     }
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -113,7 +111,7 @@ contract OpenEndedHandler is BaseHandler {
         useFuzzedStream(streamIndexSeed)
         useFuzzedStreamSender
     {
-        // Canceled streams cannot be deposited into.
+        // Only non canceled streams can be deposited.
         if (openEnded.isCanceled(currentStreamId)) {
             return;
         }
@@ -146,8 +144,8 @@ contract OpenEndedHandler is BaseHandler {
         useFuzzedStream(streamIndexSeed)
         useFuzzedStreamSender
     {
-        // Only canceled streams can be restarted.
-        if (!openEnded.isCanceled(currentStreamId)) {
+        // Only non canceled streams can be refunded.
+        if (openEnded.isCanceled(currentStreamId)) {
             return;
         }
 

test/utils/Utils.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity >=0.8.22;
+
+import { CommonBase } from "forge-std/src/Base.sol";
+import { StdUtils } from "forge-std/src/StdUtils.sol";
+
+abstract contract Utils is CommonBase, StdUtils {
+    /// @dev Stops the active prank and sets a new one.
+    function resetPrank(address msgSender) internal {
+        vm.stopPrank();
+        vm.startPrank(msgSender);
+    }
+}