chore: avoid using Alchemy API keys in tests due to limits (#662)

We are running into Alchemy API limits
(https://github.com/foundry-rs/forge-std/actions/runs/13545994206/job/37926743447?pr=654)
that is causing the CI to block, small refactor to avoid using hardcoded
API keys.

Author: zerosnacks

foundry.toml

@@ -5,7 +5,7 @@ optimizer_runs = 200
 
 [rpc_endpoints]
 # The RPC URLs are modified versions of the default for testing initialization.
-mainnet = "https://eth-mainnet.alchemyapi.io/v2/WV407BEiBmjNJfKo9Uo_55u0z0ITyCOX" # Different API key.
+mainnet = "https://eth.merkle.io" # Different API key.
 optimism_sepolia = "https://sepolia.optimism.io/" # Adds a trailing slash.
 arbitrum_one_sepolia = "https://sepolia-rollup.arbitrum.io/rpc/" # Adds a trailing slash.
 needs_undefined_env_var = "${UNDEFINED_RPC_URL_PLACEHOLDER}"

src/StdChains.sol

@@ -196,9 +196,7 @@ abstract contract StdChains {
 
         // If adding an RPC here, make sure to test the default RPC URL in `test_Rpcs` in `StdChains.t.sol`
         setChainWithDefaultRpcUrl("anvil", ChainData("Anvil", 31337, "http://127.0.0.1:8545"));
-        setChainWithDefaultRpcUrl(
-            "mainnet", ChainData("Mainnet", 1, "https://eth-mainnet.alchemyapi.io/v2/pwc5rmJhrdoaSEfimoKEmsvOjKSmPDrP")
-        );
+        setChainWithDefaultRpcUrl("mainnet", ChainData("Mainnet", 1, "https://eth.llamarpc.com"));
         setChainWithDefaultRpcUrl(
             "sepolia", ChainData("Sepolia", 11155111, "https://sepolia.infura.io/v3/b9794ad1ddf84dfb8c34d6bb5dca2001")
         );

test/StdChains.t.sol

@@ -24,7 +24,7 @@ contract StdChainsMock is Test {
 contract StdChainsTest is Test {
     function test_ChainRpcInitialization() public {
         // RPCs specified in `foundry.toml` should be updated.
-        assertEq(getChain(1).rpcUrl, "https://eth-mainnet.alchemyapi.io/v2/WV407BEiBmjNJfKo9Uo_55u0z0ITyCOX");
+        assertEq(getChain(1).rpcUrl, "https://eth.merkle.io");
         assertEq(getChain("optimism_sepolia").rpcUrl, "https://sepolia.optimism.io/");
         assertEq(getChain("arbitrum_one_sepolia").rpcUrl, "https://sepolia-rollup.arbitrum.io/rpc/");
 
@@ -36,7 +36,7 @@ contract StdChainsTest is Test {
 
         // Cannot override RPCs defined in `foundry.toml`
         vm.setEnv("MAINNET_RPC_URL", "myoverride2");
-        assertEq(getChain("mainnet").rpcUrl, "https://eth-mainnet.alchemyapi.io/v2/WV407BEiBmjNJfKo9Uo_55u0z0ITyCOX");
+        assertEq(getChain("mainnet").rpcUrl, "https://eth.merkle.io");
 
         // Other RPCs should remain unchanged.
         assertEq(getChain(31337).rpcUrl, "http://127.0.0.1:8545");

test/StdCheats.t.sol

@@ -459,15 +459,18 @@ contract StdCheatsMock is StdCheats {
 }
 
 contract StdCheatsForkTest is Test {
-    address internal constant SHIB = 0x95aD61b0a150d79219dCF64E1E6Cc01f0B64C4cE;
-    address internal constant USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;
     address internal constant USDC_BLACKLISTED_USER = 0x1E34A77868E19A6647b1f2F47B51ed72dEDE95DD;
-    address internal constant USDT = 0xdAC17F958D2ee523a2206206994597C13D831ec7;
     address internal constant USDT_BLACKLISTED_USER = 0x8f8a8F4B54a2aAC7799d7bc81368aC27b852822A;
 
+    MockUSDT public USDT;
+    MockUSDC public USDC;
+
     function setUp() public {
-        // All tests of the `assumeNotBlacklisted` method are fork tests using live contracts.
-        vm.createSelectFork({urlOrAlias: "mainnet", blockNumber: 16_428_900});
+        USDT = new MockUSDT();
+        USDC = new MockUSDC();
+
+        USDC.setBlacklisted(USDC_BLACKLISTED_USER, true);
+        USDT.setBlacklisted(USDT_BLACKLISTED_USER, true);
     }
 
     function test_RevertIf_CannotAssumeNoBlacklisted_EOA() external {
@@ -479,41 +482,67 @@ contract StdCheatsForkTest is Test {
     }
 
     function testFuzz_AssumeNotBlacklisted_TokenWithoutBlacklist(address addr) external view {
-        assumeNotBlacklisted(SHIB, addr);
+        assumeNotBlacklisted(address(USDC), addr);
+        assumeNotBlacklisted(address(USDT), addr);
         assertTrue(true);
     }
 
     function test_RevertIf_AssumeNoBlacklisted_USDC() external {
         // We deploy a mock version so we can properly test the revert.
         StdCheatsMock stdCheatsMock = new StdCheatsMock();
         vm.expectRevert();
-        stdCheatsMock.exposed_assumeNotBlacklisted(USDC, USDC_BLACKLISTED_USER);
+        stdCheatsMock.exposed_assumeNotBlacklisted(address(USDC), USDC_BLACKLISTED_USER);
     }
 
     function testFuzz_AssumeNotBlacklisted_USDC(address addr) external view {
-        assumeNotBlacklisted(USDC, addr);
+        assumeNotBlacklisted(address(USDC), addr);
         assertFalse(USDCLike(USDC).isBlacklisted(addr));
     }
 
     function test_RevertIf_AssumeNoBlacklisted_USDT() external {
         // We deploy a mock version so we can properly test the revert.
         StdCheatsMock stdCheatsMock = new StdCheatsMock();
         vm.expectRevert();
-        stdCheatsMock.exposed_assumeNotBlacklisted(USDT, USDT_BLACKLISTED_USER);
+        stdCheatsMock.exposed_assumeNotBlacklisted(address(USDT), USDT_BLACKLISTED_USER);
     }
 
     function testFuzz_AssumeNotBlacklisted_USDT(address addr) external view {
-        assumeNotBlacklisted(USDT, addr);
+        assumeNotBlacklisted(address(USDT), addr);
         assertFalse(USDTLike(USDT).isBlackListed(addr));
     }
+}
+
+/// @dev https://etherscan.io/token/0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48#readProxyContract
+interface USDCLike {
+    function isBlacklisted(address) external view returns (bool);
+}
 
-    function test_dealUSDC() external {
-        // roll fork to the point when USDC contract updated to store balance in packed slots
-        vm.rollFork(19279215);
+/// @dev https://etherscan.io/token/0xdac17f958d2ee523a2206206994597c13d831ec7#readContract
+interface USDTLike {
+    function isBlackListed(address) external view returns (bool);
+}
+
+contract MockUSDT is USDTLike {
+    mapping(address => bool) private blacklist;
 
-        uint256 balance = 100e6;
-        deal(USDC, address(this), balance);
-        assertEq(IERC20(USDC).balanceOf(address(this)), balance);
+    function isBlackListed(address addr) external view returns (bool) {
+        return blacklist[addr];
+    }
+
+    function setBlacklisted(address addr, bool value) external {
+        blacklist[addr] = value;
+    }
+}
+
+contract MockUSDC is USDCLike {
+    mapping(address => bool) private blacklist;
+
+    function isBlacklisted(address addr) external view returns (bool) {
+        return blacklist[addr];
+    }
+
+    function setBlacklisted(address addr, bool value) external {
+        blacklist[addr] = value;
     }
 }
 
@@ -587,14 +616,6 @@ contract BarERC721 {
     mapping(address => uint256) private _balances;
 }
 
-interface USDCLike {
-    function isBlacklisted(address) external view returns (bool);
-}
-
-interface USDTLike {
-    function isBlackListed(address) external view returns (bool);
-}
-
 contract RevertingContract {
     constructor() {
         revert();