Fixed one test case based on the operating system in order to generat…

…e the exception "URI path component is empty". Also, attempted to make tests run and pass both in windows and linux by changing the file separator if the OS is Windows.

core/src/test/kotlin/org/evomaster/core/problem/rest/OpenAPILocalURLIssueTest.kt

@@ -153,10 +153,15 @@ class OpenAPILocalURLIssueTest {
             swagger = OpenApiAccess.getOpenAPIFromURL(urlToTest)
         }
 
-        // The message in the SutException should be "The file path provided for the OpenAPI Schema
-        // $urlToTest , is not a valid path"
-        Assertions.assertTrue(exception.message!!.contains("The file path provided for the OpenAPI Schema " +
-                "$urlToTest," + " ended up with the following error: "))
+        // In windows, the file cannot be located, in others the error is URL related
+        if (hostOs.contains("win")) {
+            Assertions.assertTrue(exception.message!!.contains("The provided swagger file " +
+                    "does not exist: $urlToTest"))
+        }
+        else {
+            Assertions.assertTrue(exception.message!!.contains("The file path provided for the OpenAPI Schema " +
+                    "$urlToTest," + " ended up with the following error: "))
+        }
     }
 
     @Test