winit-sonoma-fix/tests/headless.rs

extern crate glutin;
extern crate libc;

mod gl {
    include!(concat!(env!("OUT_DIR"), "/test_gl_bindings.rs"));
}

#[cfg(feature = "headless")]
#[test]
fn main() {
    let window = glutin::HeadlessRendererBuilder::new(1024, 768).build().unwrap();

    unsafe { window.make_current() };

    let gl = gl::Gl::load_with(|symbol| window.get_proc_address(symbol));

    unsafe {
        gl.ClearColor(0.0, 1.0, 0.0, 1.0);
        gl.Clear(gl::COLOR_BUFFER_BIT);

        let mut value: (u8, u8, u8, u8) = std::mem::uninitialized();
        gl.ReadPixels(0, 0, 1, 1, gl::RGBA, gl::UNSIGNED_BYTE, std::mem::transmute(&mut value));
        
        assert!(value == (0, 255, 0, 255) || value == (0, 64, 0, 255) ||
                value == (0, 64, 0, 255) || value == (0, 64, 0, 0),
                "value is: {:?}", value);
    }
}