feat(cheatcodes): implement new cheatcode to check if a string contains another string

crates/cheatcodes/spec/src/vm.rs

@@ -1976,6 +1976,9 @@ interface Vm {
     /// Returns 0 in case of an empty `key`.
     #[cheatcode(group = String)]
     function indexOf(string calldata input, string calldata key) external pure returns (uint256);
+    /// Returns true if `search` is found in `subject`, false otherwise.
+    #[cheatcode(group = String)]
+    function contains(string calldata subject, string calldata search) external returns (bool result);
 
     // ======== JSON Parsing and Manipulation ========
 

crates/cheatcodes/src/string.rs

@@ -144,6 +144,14 @@ impl Cheatcode for indexOfCall {
     }
 }
 
+// contains
+impl Cheatcode for containsCall {
+    fn apply(&self, _state: &mut Cheatcodes) -> Result {
+        let Self { subject, search } = self;
+        Ok(subject.contains(search).abi_encode())
+    }
+}
+
 pub(super) fn parse(s: &str, ty: &DynSolType) -> Result {
     parse_value(s, ty).map(|v| v.abi_encode())
 }

testdata/default/cheats/StringUtils.t.sol

@@ -51,4 +51,10 @@ contract StringManipulationTest is DSTest {
         assertEq(vm.indexOf(input, key3), 0);
         assertEq(vm.indexOf(input, key4), type(uint256).max);
     }
+
+    function testContains() public {
+        string memory subject = "this is a test";
+        assert(vm.contains(subject, "test"));
+        assert(!vm.contains(subject, "foundry"));
+    }
 }