Added the tests for the 'withError' function

src/main/scala/in/rcard/raise4s/Raise.scala

@@ -52,5 +52,5 @@ def $catch[A](block: () => A, catchBlock: Throwable => A): A =
 def withError[Error, OtherError, A](
     transform: OtherError => Error,
     block: Raise[OtherError] ?=> () => A
-)(using r: Raise[Error]) =
+)(using r: Raise[Error]): A =
   recover(block, otherError => r.raise(transform(otherError)))

src/test/scala/in/rcard/raise4s/RaiseSpec.scala

@@ -124,4 +124,20 @@ class RaiseSpec extends AnyFlatSpec with Matchers {
       )
     }
   }
+
+  "withError" should "return the value if it is not an error" in {
+    val actual = either {
+      () => withError[Int, String, Int](s => s.length, () => 42)
+    }
+
+    actual should be(Right(42))
+  }
+
+  it should "return the transformed error if the value is an error" in {
+    val actual = either {
+      () => withError[Int, String, Int](s => s.length, () => raise("error"))
+    }
+
+    actual should be(Left(5))
+  }
 }