Update test for new behavior and fix a warning in swift 5.0+ compiler code

Author: klundberg

Sources/RefResolver.swift

@@ -1,9 +1,15 @@
 import Foundation
 
 func urlSplitFragment(url: String) -> (String, String) {
+  #if swift(>=5.0)
+  guard let hashIndex = url.firstIndex(of: "#") else {
+    return (url, "")
+  }
+  #else
   guard let hashIndex = url.index(of: "#") else {
     return (url, "")
   }
+  #endif
 
   return (
     String(url.prefix(upTo: hashIndex)),

Tests/JSONSchemaTests/Validation/TestRequired.swift

@@ -21,7 +21,7 @@ public let testRequired: ((ContextType) -> Void) = {
       let error = errors[0]
 
       try expect(error.description) == "Required property 'test' is missing"
-      try expect(error.instanceLocation.path) == "/0"
+      try expect(error.instanceLocation.path) == "/0/test"
       try expect(error.keywordLocation.path) == "#/items/required"
     }
   }