feat: Storage accessible unit tests

test/reader/StorageAccessible.t.sol

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+pragma solidity >=0.7.6 <0.9.0;
+pragma abicoder v2;
+
+import {Test, Vm} from "forge-std/Test.sol";
+import {StorageAccessibleWrapper, ExternalStorageReader} from "src/contracts/test/vendor/StorageAccessibleWrapper.sol";
+import {ViewStorageAccessible} from "src/contracts/mixins/StorageAccessible.sol";
+
+contract StorageAccessibleTest is Test {
+    StorageAccessibleWrapper instance;
+    ExternalStorageReader reader;
+
+    function setUp() public {
+        instance = new StorageAccessibleWrapper();
+        reader = new ExternalStorageReader();
+    }
+
+    function test_can_invoke_function_in_the_context_of_previously_deployed_contract() public {
+        instance.setFoo(42);
+        bytes memory data = instance.simulateDelegatecall(address(reader), abi.encodeWithSignature("getFoo()"));
+        uint256 result = abi.decode(data, (uint256));
+        assertEq(result, 42);
+    }
+
+    function test_can_simulateDelegatecall_a_function_with_side_effects() public {
+        instance.setFoo(42);
+        vm.startStateDiffRecording();
+
+        bytes memory data =
+            instance.simulateDelegatecall(address(reader), abi.encodeWithSignature("setAndGetFoo(uint256)", 69));
+        uint256 result = abi.decode(data, (uint256));
+        assertEq(result, 69);
+
+        // Make sure foo is not actually changed
+        uint256 foo = reader.invokeStaticDelegatecall(
+            ViewStorageAccessible(address(instance)), abi.encodeWithSignature("getFoo()")
+        );
+        assertEq(foo, 42);
+
+        // Using state changes to make sure foo isn't changed
+        Vm.AccountAccess[] memory records = vm.stopAndReturnStateDiff();
+        for (uint256 i; i < records.length; i++) {
+            uint256 storageCalls = records[i].storageAccesses.length;
+            for (uint256 j; j < storageCalls; j++) {
+                if (records[i].storageAccesses[j].isWrite) {
+                    assertEq(records[i].storageAccesses[j].reverted, true);
+                }
+            }
+        }
+    }
+
+    function test_can_simulateDelegatecall_a_function_that_reverts() public {
+        vm.expectRevert();
+        instance.simulateDelegatecall(address(reader), abi.encodeWithSignature("doRevert()"));
+    }
+
+    function test_allows_detection_of_reverts_when_invoked_from_other_smart_contract() public {
+        vm.expectRevert();
+        reader.invokeDoRevertViaStorageAccessible(instance);
+    }
+}

test/reader/ViewStorageAccessible.t.sol

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+pragma solidity >=0.7.6 <0.9.0;
+pragma abicoder v2;
+
+import {Test} from "forge-std/Test.sol";
+import {StorageAccessibleWrapper, ExternalStorageReader} from "src/contracts/test/vendor/StorageAccessibleWrapper.sol";
+import {ViewStorageAccessible} from "src/contracts/mixins/StorageAccessible.sol";
+
+contract StorageAccessibleTest is Test {
+    StorageAccessibleWrapper instance;
+    ExternalStorageReader reader;
+
+    function setUp() public {
+        instance = new StorageAccessibleWrapper();
+        reader = new ExternalStorageReader();
+    }
+
+    function test_simulate() public {
+        instance.setFoo(42);
+        uint256 result = reader.invokeStaticDelegatecall(
+            ViewStorageAccessible(address(instance)), abi.encodeWithSignature("getFoo()")
+        );
+        assertEq(result, 42);
+    }
+
+    function test_cannot_simulate_state_changes() public {
+        instance.setFoo(42);
+        vm.expectRevert();
+        reader.invokeStaticDelegatecall(
+            ViewStorageAccessible(address(instance)), abi.encodeWithSignature("setAndGetFoo(uint256)", 69)
+        );
+    }
+}