public void TestExceptions()
{
var fs = new MemoryFileSystem();
Assert.Throws <ArgumentNullException>(() => fs.AppendAllText("/a.txt", null));
Assert.Throws <ArgumentNullException>(() => fs.WriteAllText("/a.txt", null));
Assert.Throws <ArgumentNullException>(() => fs.WriteAllText("/a.txt", "content", null));
Assert.Throws <ArgumentNullException>(() => fs.WriteAllText("/a.txt", null, null));
Assert.Throws <ArgumentNullException>(() => fs.ReadAllText("/a.txt", null));
Assert.Throws <ArgumentNullException>(() => fs.ReadAllLines("/a.txt", null));
Assert.Throws <ArgumentNullException>(() => fs.WriteAllBytes("/a", null));
Assert.Throws <ArgumentNullException>(() => fs.AppendAllText("/a", null, null));
Assert.Throws <ArgumentNullException>(() => fs.AppendAllText("/a", "content", null));
Assert.Throws <ArgumentNullException>(() => fs.EnumeratePaths("*", null).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumeratePaths("*", null, SearchOption.AllDirectories).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateFiles("*", null).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateFiles("*", null, SearchOption.AllDirectories).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateDirectories("*", null).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateDirectories("*", null, SearchOption.AllDirectories).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateFileEntries("*", null).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateFileEntries("*", null, SearchOption.AllDirectories).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateDirectoryEntries("*", null).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateDirectoryEntries("*", null, SearchOption.AllDirectories).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateFileSystemEntries("*", null).First());
Assert.Throws <ArgumentNullException>(() => fs.EnumerateFileSystemEntries("*", null, SearchOption.AllDirectories).First());
Assert.Throws <FileNotFoundException>(() => fs.GetFileEntry("/a.txt"));
Assert.Throws <DirectoryNotFoundException>(() => fs.GetDirectoryEntry("/a"));
}