PsGet.Abstractions.PhysicalFileSystem.OpenFile C# (CSharp) Method

        public Stream OpenFile(string fileName)
        {
            string fullPath = GetFullPath(fileName);
            string parent = Path.GetDirectoryName(fullPath);
            if (!Directory.Exists(parent))
            {
                Directory.CreateDirectory(parent);
            }
            return File.Open(fullPath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);
        }

        public void OpenFileReturnsWriteableStreamPositionedAtFileStart()
        {
            // Arrange
            PhysicalFileSystem fs = new PhysicalFileSystem(testRoot);
            WriteTestFile("testOpenWrite.txt", "Foo Bar Baz");

            // Act
            using (Stream strm = fs.OpenFile("testOpenWrite.txt"))
            {
                using (StreamWriter writer = new StreamWriter(strm))
                {
                    writer.Write("Quz");
                }
            }

            // Assert
            Assert.Equal("Quz Bar Baz", File.ReadAllText(ResolveTestFile("testOpenWrite.txt")));
        }