Expect the scanner's enum error for a directive enum in a Map input

The directive enum test from #852 expected the parser's "Expected enum
with name 'Purpose' but found none!" for an enum that's also used by an
input field bound to a Map. With this branch the scanner already fails
for that enum, since no class can be found for it, and names the input
type, the field and how to fix it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: oryan-block

src/test/kotlin/graphql/kickstart/tools/SchemaClassScannerDirectiveTest.kt

@@ -249,7 +249,7 @@ class SchemaClassScannerDirectiveTest {
             missingEnum)
 
         // an input field bound to a Map, which would get the enum's values
-        assertSchemaError(
+        val mapError = assertThrows(SchemaClassScannerError::class.java) {
             SchemaParser.newParser()
                 .schemaString(linkDirective)
                 .schemaString(
@@ -258,8 +258,12 @@ class SchemaClassScannerDirectiveTest {
 
                     type Query { hello(filter: Filter!): String }
                     """)
-                .resolvers(object : GraphQLQueryResolver { fun hello(filter: Map<String, Any>): String = filter.toString() }),
-            missingEnum)
+                .resolvers(object : GraphQLQueryResolver { fun hello(filter: Map<String, Any>): String = filter.toString() })
+                .build()
+        }
+        assertEquals(mapError.message, "Enum type 'Purpose' is used by field 'purpose' of input type 'Filter', but its Java enum can't be determined " +
+            "because 'Filter' is bound to java.util.Map, which has no type information for its fields. Pass the enum class for type " +
+            "'Purpose' in the parser's dictionary, or use a class for 'Filter' with a public getter or field 'purpose'.")
 
         // an argument of an unimplemented field added by an extension
         assertSchemaError(