Update ERC-20 unit tests

src/diamond/example/ExampleDiamond.sol

@@ -41,7 +41,9 @@ contract ExampleDiamond {
         /**
          * Setting ERC721 token details
          */
-        ERC721MetadataMod.setMetadata({_name: "ExampleDiamondNFT", _symbol: "EDN", _baseURI: "https://example.com/metadata/"});
+        ERC721MetadataMod.setMetadata({
+            _name: "ExampleDiamondNFT", _symbol: "EDN", _baseURI: "https://example.com/metadata/"
+        });
         /**
          * Registering ERC165 interfaces
          */

src/token/ERC20/Approve/ERC20ApproveMod.sol

@@ -51,12 +51,14 @@ function getStorage() pure returns (ERC20Storage storage s) {
  * @dev Sets the allowance for the spender.
  * @param _spender The address to approve for spending.
  * @param _value The amount of tokens to approve.
+ * @return True if the approval was successful.
  */
-function approve(address _spender, uint256 _value) {
+function approve(address _spender, uint256 _value) returns (bool) {
     if (_spender == address(0)) {
         revert ERC20InvalidSpender(address(0));
     }
     ERC20Storage storage s = getStorage();
     s.allowance[msg.sender][_spender] = _value;
     emit Approval(msg.sender, _spender, _value);
+    return true;
 }

src/token/ERC20/Transfer/ERC20TransferMod.sol

@@ -94,8 +94,9 @@ function getStorage() pure returns (ERC20Storage storage s) {
  * @param _from The address to send tokens from.
  * @param _to The address to send tokens to.
  * @param _value The number of tokens to transfer.
+ * @return True if the transfer was successful.
  */
-function transferFrom(address _from, address _to, uint256 _value) {
+function transferFrom(address _from, address _to, uint256 _value) returns (bool) {
     ERC20Storage storage s = getStorage();
     if (_from == address(0)) {
         revert ERC20InvalidSender(address(0));
@@ -119,15 +120,17 @@ function transferFrom(address _from, address _to, uint256 _value) {
     }
     s.balanceOf[_to] += _value;
     emit Transfer(_from, _to, _value);
+    return true;
 }
 
 /**
  * @notice Transfers tokens from the caller to another address.
  * @dev Updates balances directly without allowance mechanism.
  * @param _to The address to send tokens to.
  * @param _value The number of tokens to transfer.
+ * @return True if the transfer was successful.
  */
-function transfer(address _to, uint256 _value) {
+function transfer(address _to, uint256 _value) returns (bool) {
     ERC20Storage storage s = getStorage();
     if (_to == address(0)) {
         revert ERC20InvalidReceiver(address(0));
@@ -141,5 +144,6 @@ function transfer(address _to, uint256 _value) {
     }
     s.balanceOf[_to] += _value;
     emit Transfer(msg.sender, _to, _value);
+    return true;
 }
 

test/Base.t.sol

@@ -36,9 +36,9 @@ abstract contract Base_Test is Constants, Modifiers, StdAssertions, StdCheats {
         createTestUsers();
         defaults.setUsers(users);
 
-        setVariables(defaults, users); // set in modifier contract
+        setVariables(defaults, users);
 
-        setMsgSender(users.alice); // alice default caller
+        setMsgSender(users.alice);
     }
 
     /*//////////////////////////////////////////////////////////////

test/harnesses/token/ERC20/ERC20ApproveModHarness.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+import "src/token/ERC20/Approve/ERC20ApproveMod.sol" as ERC20ApproveMod;
+
+/**
+ * @title ERC20ApproveModHarness
+ * @notice Test harness that exposes ERC20ApproveMod functions as external
+ */
+contract ERC20ApproveModHarness {
+    /**
+     * @notice Exposes ERC20ApproveMod.approve as an external function
+     */
+    function approve(address _spender, uint256 _value) external returns (bool) {
+        return ERC20ApproveMod.approve(_spender, _value);
+    }
+}

test/harnesses/token/ERC20/ERC20BurnModHarness.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+import "src/token/ERC20/Burn/ERC20BurnMod.sol" as ERC20BurnMod;
+
+/**
+ * @title ERC20BurnModHarness
+ * @notice Test harness that exposes ERC20BurnMod functions as external
+ */
+contract ERC20BurnModHarness {
+    /**
+     * @notice Exposes ERC20BurnMod.burnERC20 as an external function
+     */
+    function burn(address _account, uint256 _value) external {
+        ERC20BurnMod.burnERC20(_account, _value);
+    }
+}

test/harnesses/token/ERC20/ERC20MintModHarness.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+import "src/token/ERC20/Mint/ERC20MintMod.sol" as ERC20MintMod;
+
+/**
+ * @title ERC20MintModHarness
+ * @notice Test harness that exposes ERC20MintMod functions as external
+ */
+contract ERC20MintModHarness {
+    /**
+     * @notice Exposes ERC20Mod.mintERC20 as an external function
+     */
+    function mint(address _account, uint256 _value) external {
+        ERC20MintMod.mintERC20(_account, _value);
+    }
+}

test/harnesses/token/ERC20/ERC20TransferModHarness.sol

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+import "src/token/ERC20/Transfer/ERC20TransferMod.sol" as ERC20TransferMod;
+
+/**
+ * @title ERC20TransferModHarness
+ * @notice Test harness that exposes ERC20TransferMod functions as external
+ */
+contract ERC20TransferModHarness {
+    /**
+     * @notice Exposes ERC20TransferMod.transferFrom as an external function
+     */
+    function transferFrom(address _from, address _to, uint256 _value) external returns (bool) {
+        return ERC20TransferMod.transferFrom(_from, _to, _value);
+    }
+
+    /**
+     * @notice Exposes ERC20TransferMod.transfer as an external function
+     */
+    function transfer(address _to, uint256 _value) external returns (bool) {
+        return ERC20TransferMod.transfer(_to, _value);
+    }
+}

test/unit/token/ERC20/Approve/facet/fuzz/approve.t.sol

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/* Compose
+ * https://compose.diamonds
+ */
+
+import {stdError} from "forge-std/StdError.sol";
+import {Base_Test} from "test/Base.t.sol";
+import {ERC20StorageUtils} from "test/utils/storage/ERC20StorageUtils.sol";
+
+import {ERC20ApproveFacet} from "src/token/ERC20/Approve/ERC20ApproveFacet.sol";
+
+/**
+ *  @dev BTT spec: test/trees/ERC20.tree
+ */
+contract Approve_ERC20ApproveFacet_Fuzz_Unit_Test is Base_Test {
+    using ERC20StorageUtils for address;
+
+    ERC20ApproveFacet internal facet;
+
+    function setUp() public virtual override {
+        Base_Test.setUp();
+        facet = new ERC20ApproveFacet();
+        vm.label(address(facet), "ERC20ApproveFacet");
+    }
+
+    function testFuzz_ShouldRevert_SpenderIsZeroAddress(uint256 value) external {
+        vm.expectRevert(abi.encodeWithSelector(ERC20ApproveFacet.ERC20InvalidSpender.selector, ADDRESS_ZERO));
+        facet.approve(ADDRESS_ZERO, value);
+    }
+
+    function testFuzz_Approve(address spender, uint256 value) external whenSpenderNotZeroAddress {
+        vm.assume(spender != ADDRESS_ZERO);
+
+        vm.expectEmit(address(facet));
+        emit ERC20ApproveFacet.Approval(users.alice, spender, value);
+        bool result = facet.approve(spender, value);
+
+        assertEq(result, true, "approve failed");
+        assertEq(address(facet).allowance(users.alice, spender), value);
+    }
+}
+

test/unit/token/ERC20/ERC20/mod/fuzz/approve.t.sol → test/unit/token/ERC20/Approve/mod/fuzz/approve.t.sol

@@ -7,19 +7,22 @@ pragma solidity >=0.8.30;
 
 import {stdError} from "forge-std/StdError.sol";
 import {Base_Test} from "test/Base.t.sol";
-import {ERC20Harness} from "test/harnesses/token/ERC20/ERC20/ERC20Harness.sol";
+import {ERC20StorageUtils} from "test/utils/storage/ERC20StorageUtils.sol";
+import {ERC20ApproveModHarness} from "test/harnesses/token/ERC20/ERC20ApproveModHarness.sol";
 
-import "src/token/ERC20/ERC20/ERC20Mod.sol";
+import "src/token/ERC20/Approve/ERC20ApproveMod.sol";
 
 /**
  *  @dev BTT spec: test/trees/ERC20.tree
  */
-contract Approve_ERC20Mod_Fuzz_Unit_Test is Base_Test {
-    ERC20Harness internal harness;
+contract Approve_ERC20ApproveMod_Fuzz_Unit_Test is Base_Test {
+    using ERC20StorageUtils for address;
+
+    ERC20ApproveModHarness internal harness;
 
     function setUp() public override {
         Base_Test.setUp();
-        harness = new ERC20Harness();
+        harness = new ERC20ApproveModHarness();
     }
 
     function testFuzz_ShouldRevert_SpenderIsZeroAddress(uint256 value) external {
@@ -35,6 +38,6 @@ contract Approve_ERC20Mod_Fuzz_Unit_Test is Base_Test {
         bool result = harness.approve(spender, value);
 
         assertEq(result, true, "approve failed");
-        assertEq(harness.allowance(users.alice, spender), value);
+        assertEq(address(harness).allowance(users.alice, spender), value);
     }
 }