def test_native_image_cache
url="http://mirrors.apple2.org.za/ftp.apple.asimov.net/images/graphics/printshop/Print%20Shop%20Graphics%20Library%20-%20Volume%201%20-%20Back.dsk"
image_file=file_cache.get_file_system_image(url)
native_file=image_file.pictures[0]
file_cache.purge_native_file_from_cache(native_file)
cached_native_file_filename=file_cache.cache_name_for_native_file(native_file,'png')
assert(!File.exists?( cached_native_file_filename),"purging native file from cache should remove file from disk")
assert_equal(cached_native_file_filename,file_cache.force_native_file_to_cache(native_file,:to_picture,'png'),"force_native_file_to_cache should return path of cached file when it DOES write to disk")
assert_equal(cached_native_file_filename,file_cache.force_native_file_to_cache(native_file,:to_picture,'png'),"force_native_file_to_cache should return path of cached file when it DOES NOT write to disk")
assert(File.exists?(cached_native_file_filename),"forcing native file to native file cache should result in #{cached_native_file_filename} existing on disk")
end