initial copy and modifications from the original py/impl/test/dist and

looponfail code. Now works as its own "xdist" plugin.

testing/test_util.py

@@ -0,0 +1,61 @@
+import py
+from xdist.util import StatRecorder
+
+def test_filechange(tmpdir):
+    tmp = tmpdir
+    hello = tmp.ensure("hello.py")
+    sd = StatRecorder([tmp])
+    changed = sd.check()
+    assert not changed
+
+    hello.write("world")
+    changed = sd.check()
+    assert changed
+
+    tmp.ensure("new.py")
+    changed = sd.check()
+    assert changed
+    
+    tmp.join("new.py").remove()
+    changed = sd.check()
+    assert changed
+
+    tmp.join("a", "b", "c.py").ensure()
+    changed = sd.check()
+    assert changed
+
+    tmp.join("a", "c.txt").ensure()
+    changed = sd.check()
+    assert changed
+    changed = sd.check()
+    assert not changed
+
+    tmp.join("a").remove()
+    changed = sd.check()
+    assert changed
+
+def test_pycremoval(tmpdir):
+    tmp = tmpdir
+    hello = tmp.ensure("hello.py")
+    sd = StatRecorder([tmp])
+    changed = sd.check()
+    assert not changed
+
+    pycfile = hello + "c"
+    pycfile.ensure()
+    changed = sd.check()
+    assert not changed 
+
+    hello.write("world")
+    changed = sd.check()
+    assert not pycfile.check()
+    
+
+def test_waitonchange(tmpdir, monkeypatch):
+    tmp = tmpdir
+    sd = StatRecorder([tmp])
+
+    l = [True, False]
+    monkeypatch.setattr(StatRecorder, 'check', lambda self: l.pop())
+    sd.waitonchange(checkinterval=0.2)
+    assert not l