public void GivenPath_AndContentExists_WhenReadAllText_ThenFileContentsReturned() { // Arrange var id = Guid.NewGuid().ToString(); var path = $"{id}.txt"; var contents = id; File.WriteAllText( path, contents); _tempFiles.Add(path); var sut = new FileIOService(); // Act var result = sut.ReadAllText(path); // Assert Assert.Equal(contents, result); }