Fix for File::isDirectory on posix when given a File::nonexistent. Also added unit tests for this.

modules/juce_core/files/juce_File.cpp

@@ -916,6 +916,11 @@ public:
         const File temp (File::getSpecialLocation (File::tempDirectory));
 
         expect (! File::nonexistent.exists());
+        expect (! File::nonexistent.existsAsFile());
+        expect (! File::nonexistent.isDirectory());
+       #if ! JUCE_WINDOWS
+        expect (File("/").isDirectory());
+       #endif
         expect (home.isDirectory());
         expect (home.exists());
         expect (! home.existsAsFile());

modules/juce_core/native/juce_posix_SharedCode.h

@@ -265,8 +265,8 @@ bool File::isDirectory() const
 {
     juce_statStruct info;
 
-    return fullPath.isEmpty()
-            || (juce_stat (fullPath, info) && ((info.st_mode & S_IFDIR) != 0));
+    return fullPath.isNotEmpty()
+             && (juce_stat (fullPath, info) && ((info.st_mode & S_IFDIR) != 0));
 }
 
 bool File::exists() const