Add step contract test template

Author: pcw109550

Diff for: rvsol/test/Step.t.sol

@@ -0,0 +1,18 @@
+pragma solidity 0.8.15;
+
+import {Test} from "forge-std/Test.sol";
+import {Step} from "src/Step.sol";
+import {PreimageOracle} from "@optimism/packages/contracts-bedrock/src/cannon/PreimageOracle.sol";
+
+contract Step_Test is Test {
+    PreimageOracle internal oracle;
+    Step internal step;
+
+    function setUp() public {
+        oracle = new PreimageOracle(0, 0, 0);
+        step = new Step(oracle);
+        vm.store(address(step), 0x0, bytes32(abi.encode(address(oracle))));
+        vm.label(address(oracle), "PreimageOracle");
+        vm.label(address(step), "Step");
+    }
+}