Fix Library Load tests on Big Sur

Big Sur uses a shared dylib cache to lookup system libraries and frameworks. Checking existence in the file system will fail, but loading them will succeed nevertheless.

Author: fkistner

test/com/sun/jna/LibraryLoadTest.java

@@ -203,13 +203,12 @@ public void testLoadLibraryWithLongName() throws Exception {
     public void testLoadFrameworkLibrary() {
         if (Platform.isMac()) {
             final String PATH = "/System/Library/Frameworks/CoreServices.framework";
-            assertTrue("CoreServices not present on this setup, expected at " + PATH, new File(PATH).exists());
             try {
                 NativeLibrary lib = NativeLibrary.getInstance("CoreServices");
                 assertNotNull("CoreServices not found", lib);
             }
             catch(UnsatisfiedLinkError e) {
-                fail("Should search /System/Library/Frameworks");
+                failCoreServices("Should search /System/Library/Frameworks: ", e, PATH);
             }
         }
     }
@@ -218,31 +217,36 @@ public void testLoadFrameworkLibraryAbsolute() {
         if (Platform.isMac()) {
             final String PATH = "/System/Library/Frameworks/CoreServices";
             final String FRAMEWORK = PATH + ".framework";
-            assertTrue("CoreServices not present on this setup, expected at " + FRAMEWORK, new File(FRAMEWORK).exists());
             try {
                 NativeLibrary lib = NativeLibrary.getInstance(PATH);
                 assertNotNull("CoreServices not found", lib);
             }
             catch(UnsatisfiedLinkError e) {
-                fail("Should try FRAMEWORK.framework/FRAMEWORK if the absolute framework (truncated) path given exists: " + e);
+                failCoreServices("Should try FRAMEWORK.framework/FRAMEWORK if the absolute framework (truncated) path given exists: ", e, FRAMEWORK);
             }
         }
     }
 
     public void testLoadFrameworkLibraryAbsoluteFull() {
         if (Platform.isMac()) {
             final String PATH = "/System/Library/Frameworks/CoreServices.framework/CoreServices";
-            assertTrue("CoreServices not present on this setup, expected at " + PATH, new File(PATH).exists());
             try {
                 NativeLibrary lib = NativeLibrary.getInstance(PATH);
                 assertNotNull("CoreServices not found", lib);
             }
             catch(UnsatisfiedLinkError e) {
-                fail("Should try FRAMEWORK verbatim if the absolute path given exists: " + e);
+                failCoreServices("Should try FRAMEWORK verbatim if the absolute path given exists: ", e, PATH);
             }
         }
     }
 
+    private void failCoreServices(String message, UnsatisfiedLinkError e, String expectedPath) {
+        if (!new File(expectedPath).exists()) {
+            message = "CoreServices not present on this setup, expected at " + expectedPath + "\n" + message;
+        }
+        fail(message + e);
+    }
+
     public void testHandleObjectMethods() {
         CLibrary lib = (CLibrary)load();
         String method = "toString";