add erc20 example and update readme

README.md

@@ -72,12 +72,16 @@ The `template` command is used to generate a fuzzing harness. The harness can in
 
 **Example**
 
-In order to generate a fuzzing harness for the [BasicTypes.sol](tests/test_data/src/BasicTypes.sol) contract, we need to `cd` into the `tests/test_data/` directory which contains the Foundry project and run the command:
+In order to generate a fuzzing harness for the [TestERC20.sol](tests/test_data/src/TestERC20.sol) contract, we need to `cd` into the `tests/test_data/` directory which contains the Foundry project and run the command:
 ```bash
-fuzz-utils template ./src/BasicType.sol --name "DefaultHarness" --contracts BasicTypes
+fuzz-utils template ./src/TestERC20.sol --name "ERC20Harness" --contracts TestERC20
 ```
 
-Running this command should generate the directory structure in [tests/test_data/test/fuzzing](tests/test_data/test/fuzzing), which contains the fuzzing harness [DefaultHarness](tests/test_data/test/fuzzing/harnesses/DefaultHarness.sol) and the Actor contract [DefaultActor](tests/test_data/test/fuzzing/actors/ActorDefault.sol).
+Running this command should generate the directory structure in [tests/test_data/test/fuzzing](tests/test_data/test/fuzzing), which contains the fuzzing harness [ERC20Harness](tests/test_data/test/fuzzing/harnesses/ERC20Harness.sol) and the Actor contract [DefaultActor](tests/test_data/test/fuzzing/actors/ActorDefault.sol).
+
+We can see that the tool has generated the `DefaultActor` contract which contains all the functions of our ERC20 token, and that our fuzzing harness `ERC20Harness` is able to call each of these functions by randomly selecting one of the deployed actors, simulating different users. 
+
+This reduces the amount of time you need to set up fuzzing harness boilerplate and let's you focus on what really matters, defining invariants and testing the system.
 
 ## Utilities
 

tests/test_data/src/TestERC20.sol

@@ -0,0 +1,7 @@
+pragma solidity ^0.8.0;
+
+import {ERC20} from "solmate/tokens/ERC20.sol";
+
+contract TestERC20 is ERC20 {
+    constructor() ERC20("TestERC20", "TEST", 18) {}
+}

tests/test_data/test/fuzzing/actors/ActorDefault.sol

@@ -14,87 +14,31 @@ pragma solidity ^0.8.0;
 ///    `directoryName/=directoryName/` to foundry.toml or remappings.txt
 
 import "properties/util/PropertiesHelper.sol";
-import "src/BasicTypes.sol";
+import "src/TestERC20.sol";
 contract ActorDefault is PropertiesAsserts {
-    BasicTypes basictypes;
-    constructor(address _basictypes){
-       basictypes = BasicTypes(_basictypes);
+    TestERC20 testerc20;
+    constructor(address _testerc20){
+       testerc20 = TestERC20(_testerc20);
     }
 
     // -------------------------------------
-    // BasicTypes functions
-    // src/BasicTypes.sol
+    // ERC20 functions
+    // lib/solmate/src/tokens/ERC20.sol
     // -------------------------------------
 
-    function setBool(bool set) public {
-        basictypes.setBool(set);
+    function approve(address payable spender, uint256 amount) public returns (bool) {
+        testerc20.approve(spender, amount);
     }
 
-    function check_bool() public {
-        basictypes.check_bool();
+    function transfer(address payable to, uint256 amount) public returns (bool) {
+        testerc20.transfer(to, amount);
     }
 
-    function setUint256(uint256 input) public {
-        basictypes.setUint256(input);
+    function transferFrom(address payable from, address payable to, uint256 amount) public returns (bool) {
+        testerc20.transferFrom(from, to, amount);
     }
 
-    function check_uint256() public {
-        basictypes.check_uint256();
-    }
-
-    function check_large_uint256() public {
-        basictypes.check_large_uint256();
-    }
-
-    function setInt256(int256 input) public {
-        basictypes.setInt256(input);
-    }
-
-    function check_int256() public {
-        basictypes.check_int256();
-    }
-
-    function check_large_positive_int256() public {
-        basictypes.check_large_positive_int256();
-    }
-
-    function check_large_negative_int256() public {
-        basictypes.check_large_negative_int256();
-    }
-
-    function setAddress(address payable input) public {
-        basictypes.setAddress(input);
-    }
-
-    function check_address() public {
-        basictypes.check_address();
-    }
-
-    function setString(string memory input) public {
-        basictypes.setString(input);
-    }
-
-    function check_string() public {
-        basictypes.check_string();
-    }
-
-    function check_specific_string(string memory provided) public {
-        basictypes.check_specific_string(provided);
-    }
-
-    function setBytes(bytes memory input) public {
-        basictypes.setBytes(input);
-    }
-
-    function check_bytes() public {
-        basictypes.check_bytes();
-    }
-
-    function setCombination(bool bool_input, uint256 unsigned_input, int256 signed_input, address payable address_input, string memory str_input, bytes memory bytes_input) public {
-        basictypes.setCombination(bool_input, unsigned_input, signed_input, address_input, str_input, bytes_input);
-    }
-
-    function check_combined_input() public {
-        basictypes.check_combined_input();
+    function permit(address payable owner, address payable spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
+        testerc20.permit(owner, spender, value, deadline, v, r, s);
     }
 }

tests/test_data/test/fuzzing/harnesses/ERC20Harness.sol

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.0;
+
+/// --------------------------------------------------------------------
+/// @notice This file was automatically generated using fuzz-utils 
+///
+/// -- [ Prerequisites ]
+/// 1. The generated contracts depend on crytic/properties utilities
+///    which need to be installed, this can be done by running:
+///    `forge install crytic/properties`
+/// 2. Absolute paths are used for contract inheritance, requiring
+///    the main directory that contains the contracts to be added to
+///    the Foundry remappings. This can be done by adding:
+///    `directoryName/=directoryName/` to foundry.toml or remappings.txt
+///
+/// -- [ Running the fuzzers ]
+///    * The below commands contain example values which you can modify based
+///    on your needs. For further information on the configuration options
+///    please reference the fuzzer documentation *
+///    Echidna: echidna  --contract ERC20Harness --test-mode assertion --test-limit 100000 --corpus-dir echidna-corpora/corpus-ERC20Harness
+///    Medusa: medusa fuzz --target  --assertion-mode --test-limit 100000 --deployment-order "ERC20Harness" --corpus-dir medusa-corpora/corpus-ERC20Harness
+///    Foundry: forge test --match-contract ERC20Harness
+/// --------------------------------------------------------------------
+
+import "properties/util/PropertiesHelper.sol";
+import "src/TestERC20.sol";
+import "../actors/ActorDefault.sol";
+
+contract ERC20Harness is PropertiesAsserts {
+    TestERC20 testerc20;
+    ActorDefault[] Default_actors;
+
+    constructor() {
+        testerc20 = new TestERC20();
+        for(uint256 i; i < 3; i++) {
+            Default_actors.push(new ActorDefault(address(testerc20)));
+        }
+    }
+
+    // -------------------------------------
+    // ActorDefault functions
+    // test/fuzzing/actors/ActorDefault.sol
+    // -------------------------------------
+
+    function approve(uint256 actorIndex, address payable spender, uint256 amount) public returns (bool) {
+        ActorDefault selectedActor = Default_actors[clampBetween(actorIndex, 0, Default_actors.length - 1)];
+        selectedActor.approve(spender, amount);
+    }
+
+    function transfer(uint256 actorIndex, address payable to, uint256 amount) public returns (bool) {
+        ActorDefault selectedActor = Default_actors[clampBetween(actorIndex, 0, Default_actors.length - 1)];
+        selectedActor.transfer(to, amount);
+    }
+
+    function transferFrom(uint256 actorIndex, address payable from, address payable to, uint256 amount) public returns (bool) {
+        ActorDefault selectedActor = Default_actors[clampBetween(actorIndex, 0, Default_actors.length - 1)];
+        selectedActor.transferFrom(from, to, amount);
+    }
+
+    function permit(uint256 actorIndex, address payable owner, address payable spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
+        ActorDefault selectedActor = Default_actors[clampBetween(actorIndex, 0, Default_actors.length - 1)];
+        selectedActor.permit(owner, spender, value, deadline, v, r, s);
+    }
+}