Fix failing test

Author: MaggieKimani1

test/Microsoft.OpenApi.Tests/Walkers/WalkerLocationTests.cs

@@ -221,7 +221,9 @@ public void LocateReferences()
             locator.Locations.Where(l => l.StartsWith("referenceAt:")).Should().BeEquivalentTo(new List<string> {
                 "referenceAt: #/paths/~1/get/responses/200/content/application~1json/schema",
                 "referenceAt: #/paths/~1/get/responses/200/headers/test-header",
-                "referenceAt: #/components/schemas/derived/anyOf/0",
+                "referenceAt: #/components/schemas/derived",
+                "referenceAt: #/components/schemas/derived/anyOf",
+                "referenceAt: #/components/schemas/base",
                 "referenceAt: #/components/headers/test-header/schema"
             });
         }
@@ -291,7 +293,14 @@ public override void Visit(OpenApiMediaType mediaType)
 
         public override void Visit(ref JsonSchema schema)
         {
-            Locations.Add(this.PathString);
+            if (schema.GetRef() != null)
+            {
+                Locations.Add("referenceAt: " + this.PathString);
+            }
+            else
+            {
+                Locations.Add(this.PathString);
+            }
         }
 
         public override void Visit(IList<OpenApiTag> openApiTags)