public void TestMount()
{
var fs = new MountFileSystem();
var memfs = new MemoryFileSystem();
Assert.Throws <ArgumentNullException>(() => fs.Mount(null, memfs));
Assert.Throws <ArgumentNullException>(() => fs.Mount("/test", null));
Assert.Throws <ArgumentException>(() => fs.Mount("test", memfs));
Assert.Throws <ArgumentException>(() => fs.Mount("/", memfs));
Assert.False(fs.IsMounted("/test"));
fs.Mount("/test", memfs);
Assert.True(fs.IsMounted("/test"));
Assert.Throws <ArgumentException>(() => fs.Mount("/test", memfs));
Assert.Throws <ArgumentException>(() => fs.Mount("/test", fs));
Assert.Throws <ArgumentNullException>(() => fs.Unmount(null));
Assert.Throws <ArgumentException>(() => fs.Unmount("test"));
Assert.Throws <ArgumentException>(() => fs.Unmount("/"));
Assert.Throws <ArgumentException>(() => fs.Unmount("/test/a"));
Assert.Throws <ArgumentException>(() => fs.Unmount("/test/a/b"));
Assert.Throws <ArgumentException>(() => fs.Unmount("/test2"));
fs.Mount("/test2", memfs);
Assert.True(fs.IsMounted("/test"));
Assert.True(fs.IsMounted("/test2"));
Assert.Equal(new Dictionary <UPath, IFileSystem>()
{
{ "/test", memfs },
{ "/test2", memfs },
}, fs.GetMounts());
fs.Unmount("/test");
Assert.False(fs.IsMounted("/test"));
Assert.True(fs.IsMounted("/test2"));
fs.Unmount("/test2");
Assert.Equal(0, fs.GetMounts().Count);
var innerFs = GetCommonMemoryFileSystem();
fs.Mount("/x/y", innerFs);
fs.Mount("/x/y/b", innerFs);
Assert.True(fs.FileExists("/x/y/A.txt"));
Assert.True(fs.FileExists("/x/y/b/A.txt"));
}