feat: adds will return for result type

Sources/Mockable/Builder/FunctionBuilders/ThrowingFunctionReturnBuilder.swift

@@ -65,6 +65,22 @@ public struct ThrowingFunctionReturnBuilder<
         mocker.addReturnValue(.produce(producer), for: member)
         return .init(mocker: mocker)
     }
+
+    /// Registers a result type that automatically emits a value when successful or throws a failure
+    ///
+    /// - Parameter result: The result type wrapping a value or error.
+    /// - Returns:  The parent builder, used for chaining additional specifications.
+    @discardableResult
+    public func willHandleResult(_ result: Result<ReturnType, ErrorType>) -> ParentBuilder {
+        switch result {
+
+        case let .success(value):
+            mocker.addReturnValue(.return(value), for: member)
+        case let .failure(error):
+            mocker.addReturnValue(.throw(error), for: member)
+        }
+        return .init(mocker: mocker)
+    }
 }
 
 extension ThrowingFunctionReturnBuilder where ReturnType == Void {

Tests/MockableTests/GivenTests.swift

@@ -277,6 +277,30 @@ final class GivenTests: XCTestCase {
         XCTAssertEqual(user.age, 100)
     }
 
+    func test_givenResult_willEmitSuccess() throws {
+        let expected = User.test1
+        let result: Result<User, any Error> = .success(expected)
+
+        given(mock)
+            .getUser(for: .any)
+            .willHandleResult(result)
+
+        let actual = try mock.getUser(for: .init())
+
+        XCTAssertEqual(actual, expected)
+    }
+
+    func test_givenResult_willThrow() throws {
+        let expected = UserError.notFound
+        let result: Result<User, any Error> = .failure(expected)
+
+        given(mock)
+            .getUser(for: .any)
+            .willHandleResult(result)
+
+        XCTAssertThrowsError(try mock.getUser(for: .init()))
+    }
+
     @MainActor
     func test_givenConcurrentGivens_whenCalled_synchronizedCorrectly() async throws {
         // Register return values concurrently