diff --git a/test/solidity/LiFiDiamond.t.sol b/test/solidity/LiFiDiamond.t.sol
new file mode 100644
index 000000000..fccbd8541
--- /dev/null
+++ b/test/solidity/LiFiDiamond.t.sol
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: Unlicensed
+pragma solidity 0.8.17;
+
+import { LiFiDiamond } from "lifi/LiFiDiamond.sol";
+import { DiamondCutFacet } from "lifi/Facets/DiamondCutFacet.sol";
+import { DiamondLoupeFacet } from "lifi/Facets/DiamondLoupeFacet.sol";
+import { OwnershipFacet } from "lifi/Facets/OwnershipFacet.sol";
+import { IDiamondCut } from "lifi/Interfaces/IDiamondCut.sol";
+import { DSTest } from "ds-test/test.sol";
+import { Vm } from "forge-std/Vm.sol";
+
+contract LiFiDiamondTest is DSTest {
+    Vm internal immutable vm = Vm(HEVM_ADDRESS);
+    LiFiDiamond public diamond;
+    DiamondCutFacet public diamondCutFacet;
+    OwnershipFacet public ownershipFacet;
+    address public diamondOwner;
+
+    event DiamondCut(
+        IDiamondCut.FacetCut[] _diamondCut,
+        address _init,
+        bytes _calldata
+    );
+
+    event OwnershipTransferred(
+        address indexed previousOwner,
+        address indexed newOwner
+    );
+
+    error FunctionDoesNotExist();
+
+    function setUp() public {
+        diamondOwner = address(123456);
+        diamondCutFacet = new DiamondCutFacet();
+        ownershipFacet = new OwnershipFacet();
+
+        // prepare function selector for diamondCut (OwnershipFacet)
+        bytes4[] memory functionSelectors = new bytes4[](1);
+        functionSelectors[0] = ownershipFacet.owner.selector;
+
+        // prepare parameters for diamondCut (OwnershipFacet)
+        IDiamondCut.FacetCut[] memory cut = new IDiamondCut.FacetCut[](1);
+        cut[0] = IDiamondCut.FacetCut({
+            facetAddress: address(ownershipFacet),
+            action: IDiamondCut.FacetCutAction.Add,
+            functionSelectors: functionSelectors
+        });
+
+        diamond = new LiFiDiamond(diamondOwner, address(diamondCutFacet));
+    }
+
+    function test_DeploysWithoutErrors() public {
+        diamond = new LiFiDiamond(diamondOwner, address(diamondCutFacet));
+    }
+
+    function test_ForwardsCallsViaDelegateCall() public {
+        // only one facet with one selector is registered (diamondCut)
+        vm.startPrank(diamondOwner);
+
+        DiamondLoupeFacet diamondLoupe = new DiamondLoupeFacet();
+
+        // make sure that this call fails (without ending the test)
+        bool failed = false;
+        try DiamondLoupeFacet(address(diamond)).facetAddresses() returns (
+            address[] memory
+        ) {} catch {
+            failed = true;
+        }
+        if (!failed) revert("InvalidDiamondSetup");
+
+        // prepare function selectors
+        bytes4[] memory functionSelectors = new bytes4[](4);
+        functionSelectors[0] = diamondLoupe.facets.selector;
+        functionSelectors[1] = diamondLoupe.facetFunctionSelectors.selector;
+        functionSelectors[2] = diamondLoupe.facetAddresses.selector;
+        functionSelectors[3] = diamondLoupe.facetAddress.selector;
+
+        // prepare diamondCut
+        IDiamondCut.FacetCut[] memory cuts = new IDiamondCut.FacetCut[](1);
+        cuts[0] = IDiamondCut.FacetCut({
+            facetAddress: address(diamondLoupe),
+            action: IDiamondCut.FacetCutAction.Add,
+            functionSelectors: functionSelectors
+        });
+
+        DiamondCutFacet(address(diamond)).diamondCut(cuts, address(0), "");
+    }
+
+    function test_RevertsOnUnknownFunctionSelector() public {
+        // call random function selectors
+        bytes memory callData = hex"a516f0f3"; // getPeripheryContract(string)
+
+        vm.expectRevert(FunctionDoesNotExist.selector);
+        address(diamond).call(callData);
+    }
+
+    function test_CanReceiveETH() public {
+        (bool success, ) = address(diamond).call{ value: 1 ether }("");
+        if (!success) revert("ExternalCallFailed");
+
+        assertEq(address(diamond).balance, 1 ether);
+    }
+}
diff --git a/test/solidity/LiFiDiamondImmutable.t.sol b/test/solidity/LiFiDiamondImmutable.t.sol
new file mode 100644
index 000000000..eb95103d9
--- /dev/null
+++ b/test/solidity/LiFiDiamondImmutable.t.sol
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: Unlicensed
+pragma solidity 0.8.17;
+
+import { LiFiDiamondImmutable } from "lifi/LiFiDiamondImmutable.sol";
+import { DiamondCutFacet } from "lifi/Facets/DiamondCutFacet.sol";
+import { DiamondLoupeFacet } from "lifi/Facets/DiamondLoupeFacet.sol";
+import { OwnershipFacet } from "lifi/Facets/OwnershipFacet.sol";
+import { IDiamondCut } from "lifi/Interfaces/IDiamondCut.sol";
+import { DSTest } from "ds-test/test.sol";
+import { Vm } from "forge-std/Vm.sol";
+
+contract LiFiDiamondImmutableTest is DSTest {
+    Vm internal immutable vm = Vm(HEVM_ADDRESS);
+    LiFiDiamondImmutable public diamond;
+    DiamondCutFacet public diamondCutFacet;
+    OwnershipFacet public ownershipFacet;
+    address public diamondOwner;
+
+    event DiamondCut(
+        IDiamondCut.FacetCut[] _diamondCut,
+        address _init,
+        bytes _calldata
+    );
+
+    event OwnershipTransferred(
+        address indexed previousOwner,
+        address indexed newOwner
+    );
+
+    error FunctionDoesNotExist();
+    error OnlyContractOwner();
+
+    function setUp() public {
+        diamondOwner = address(123456);
+        diamondCutFacet = new DiamondCutFacet();
+        ownershipFacet = new OwnershipFacet();
+
+        // prepare function selector for diamondCut (OwnershipFacet)
+        bytes4[] memory functionSelectors = new bytes4[](1);
+        functionSelectors[0] = ownershipFacet.owner.selector;
+
+        // prepare parameters for diamondCut (OwnershipFacet)
+        IDiamondCut.FacetCut[] memory cut = new IDiamondCut.FacetCut[](1);
+        cut[0] = IDiamondCut.FacetCut({
+            facetAddress: address(ownershipFacet),
+            action: IDiamondCut.FacetCutAction.Add,
+            functionSelectors: functionSelectors
+        });
+
+        diamond = new LiFiDiamondImmutable(
+            diamondOwner,
+            address(diamondCutFacet)
+        );
+    }
+
+    function test_DeploysWithoutErrors() public {
+        diamond = new LiFiDiamondImmutable(
+            diamondOwner,
+            address(diamondCutFacet)
+        );
+    }
+
+    function test_ForwardsCallsViaDelegateCall() public {
+        // only one facet with one selector is registered (diamondCut)
+        vm.startPrank(diamondOwner);
+
+        DiamondLoupeFacet diamondLoupe = new DiamondLoupeFacet();
+
+        // make sure that this call fails (without ending the test)
+        bool failed = false;
+        try DiamondLoupeFacet(address(diamond)).facetAddresses() returns (
+            address[] memory
+        ) {} catch {
+            failed = true;
+        }
+        if (!failed) revert("InvalidDiamondSetup");
+
+        // prepare function selectors
+        bytes4[] memory functionSelectors = new bytes4[](4);
+        functionSelectors[0] = diamondLoupe.facets.selector;
+        functionSelectors[1] = diamondLoupe.facetFunctionSelectors.selector;
+        functionSelectors[2] = diamondLoupe.facetAddresses.selector;
+        functionSelectors[3] = diamondLoupe.facetAddress.selector;
+
+        // prepare diamondCut
+        IDiamondCut.FacetCut[] memory cuts = new IDiamondCut.FacetCut[](1);
+        cuts[0] = IDiamondCut.FacetCut({
+            facetAddress: address(diamondLoupe),
+            action: IDiamondCut.FacetCutAction.Add,
+            functionSelectors: functionSelectors
+        });
+
+        DiamondCutFacet(address(diamond)).diamondCut(cuts, address(0), "");
+    }
+
+    function test_NonOwnerCannotAddFacet() public {
+        DiamondLoupeFacet diamondLoupe = new DiamondLoupeFacet();
+
+        // prepare function selectors
+        bytes4[] memory functionSelectors = new bytes4[](4);
+        functionSelectors[0] = diamondLoupe.facets.selector;
+        functionSelectors[1] = diamondLoupe.facetFunctionSelectors.selector;
+        functionSelectors[2] = diamondLoupe.facetAddresses.selector;
+        functionSelectors[3] = diamondLoupe.facetAddress.selector;
+
+        // prepare diamondCut
+        IDiamondCut.FacetCut[] memory cuts = new IDiamondCut.FacetCut[](1);
+        cuts[0] = IDiamondCut.FacetCut({
+            facetAddress: address(diamondLoupe),
+            action: IDiamondCut.FacetCutAction.Add,
+            functionSelectors: functionSelectors
+        });
+
+        vm.expectRevert(OnlyContractOwner.selector);
+        DiamondCutFacet(address(diamond)).diamondCut(cuts, address(0), "");
+    }
+
+    function test_RevertsOnUnknownFunctionSelector() public {
+        // call random function selectors
+        bytes memory callData = hex"a516f0f3"; // getPeripheryContract(string)
+
+        vm.expectRevert(FunctionDoesNotExist.selector);
+        address(diamond).call(callData);
+    }
+
+    function test_CanReceiveETH() public {
+        (bool success, ) = address(diamond).call{ value: 1 ether }("");
+        if (!success) revert("ExternalCallFailed");
+
+        assertEq(address(diamond).balance, 1 ether);
+    }
+}
diff --git a/test/solidity/Periphery/ERC20Proxy.t.sol b/test/solidity/Periphery/ERC20Proxy.t.sol
new file mode 100644
index 000000000..0e445cb32
--- /dev/null
+++ b/test/solidity/Periphery/ERC20Proxy.t.sol
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: Unlicensed
+pragma solidity 0.8.17;
+
+import { ERC20Proxy } from "lifi/Periphery/ERC20Proxy.sol";
+import { DiamondCutFacet } from "lifi/Facets/DiamondCutFacet.sol";
+import { DiamondLoupeFacet } from "lifi/Facets/DiamondLoupeFacet.sol";
+import { OwnershipFacet } from "lifi/Facets/OwnershipFacet.sol";
+import { IDiamondCut } from "lifi/Interfaces/IDiamondCut.sol";
+import { DSTest } from "ds-test/test.sol";
+import { Vm } from "forge-std/Vm.sol";
+
+contract ERC20ProxyTest is DSTest {
+    Vm internal immutable vm = Vm(HEVM_ADDRESS);
+    ERC20Proxy public erc20Proxy;
+    DiamondCutFacet public diamondCutFacet;
+    OwnershipFacet public ownershipFacet;
+    address public proxyOwner;
+
+    error FunctionDoesNotExist();
+    error OnlyContractOwner();
+
+    function setUp() public {
+        proxyOwner = address(123456);
+        erc20Proxy = new ERC20Proxy(proxyOwner);
+    }
+
+    function test_DeploysWithoutErrors() public {
+        erc20Proxy = new ERC20Proxy(proxyOwner);
+
+        assertEq(erc20Proxy.owner(), proxyOwner);
+    }
+
+    function test_CannotReceiveETH() public {
+        (bool success, ) = address(erc20Proxy).call{ value: 1 ether }("");
+
+        assertTrue(
+            success == false,
+            "Contract can receive ETH but should not be able to"
+        );
+    }
+}