tests: put test cases into their own folder

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

tests/testcases/basic.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+
+import xcffib.xproto as xproto
+import xcffib
+
+conn = xcffib.connect()
+setup = conn.get_setup()
+root = setup.roots[0].root
+visual = setup.roots[0].root_visual
+depth = setup.roots[0].root_depth
+
+wid = conn.generate_id()
+conn.core.CreateWindowChecked(depth, wid, root, 0, 0, 100, 100, 0, xproto.WindowClass.InputOutput, visual, 0, []).check()
+conn.core.MapWindowChecked(wid).check()
+conn.core.UnmapWindowChecked(wid).check()
+conn.core.DestroyWindowChecked(wid).check()
+
+