Even testfor @p worked after restarting
All the commands I used(I also tried each with my Minecraft username)
/testfor @p
/testfor @p minecraft:writable_book
/testfor @p minecraft:writable_book 0 0 {pages:["win"]}
There you go, as I mentioned it only happens when I double click the game to maximize it while it's still launching and presenting the Mojang logo.
[07:52:00] [Client thread/INFO]: Setting user: Tai
[07:52:00] [Client thread/INFO]: (Session ID is token:7597d97bc9d8473382409235827c074d:5df52d8504c14f67801ca3cfc49ce17b)
[07:52:01] [Client thread/INFO]: LWJGL Version: 2.9.4
[07:52:01] [Client thread/INFO]: Reloading ResourceManager: Default
[07:52:02] [Sound Library Loader/INFO]: Starting up SoundSystem...
[07:52:02] [Thread-6/INFO]: Initializing LWJGL OpenAL
[07:52:02] [Thread-6/INFO]: (The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)
AL lib: (EE) MMDevApiOpenPlayback: Device init failed: 0x80004005
AL lib: (EE) MMDevApiOpenPlayback: Device init failed: 0x80004005
[07:52:02] [Thread-6/ERROR]: Error in class 'LibraryLWJGLOpenAL'
[07:52:02] [Thread-6/ERROR]: Unable to initialize OpenAL. Probable cause: OpenAL not supported.
[07:52:02] [Thread-6/WARN]: ERROR MESSAGE:
[07:52:02] [Thread-6/INFO]: Could not locate OpenAL library.
[07:52:02] [Thread-6/WARN]: STACK TRACE:
[07:52:02] [Thread-6/INFO]: org.lwjgl.openal.AL.create(AL.java:156)
[07:52:02] [Thread-6/INFO]: org.lwjgl.openal.AL.create(AL.java:102)
[07:52:02] [Thread-6/INFO]: org.lwjgl.openal.AL.create(AL.java:206)
[07:52:02] [Thread-6/INFO]: paulscode.sound.libraries.LibraryLWJGLOpenAL.init(LibraryLWJGLOpenAL.java:164)
[07:52:02] [Thread-6/INFO]: paulscode.sound.SoundSystem.CommandNewLibrary(SoundSystem.java:1576)
[07:52:02] [Thread-6/INFO]: paulscode.sound.SoundSystem.CommandQueue(SoundSystem.java:2572)
[07:52:02] [Thread-6/INFO]: paulscode.sound.CommandThread.run(CommandThread.java:121)
[07:52:02] [Sound Library Loader/WARN]: ERROR MESSAGE:
[07:52:02] [Sound Library Loader/INFO]: Could not locate OpenAL library.
[07:52:02] [Sound Library Loader/INFO]: Starting up SoundSystem...
[07:52:03] [Thread-8/INFO]: Switching to No Sound
[07:52:03] [Thread-8/INFO]: (Silent Mode)
[07:52:03] [Sound Library Loader/INFO]: Sound engine started
[07:52:03] [Client thread/INFO]: Created: 512x512 textures-atlas
The other two I had my commands mixed up.