make sure we get an absolute path when writing the genscript file

--HG--
branch : trunk

py/_plugin/pytest_genscript.py

@@ -25,13 +25,15 @@ def pytest_configure(config):
         mydir = py.path.local(__file__).dirpath()
         infile = mydir.join("standalonetemplate.py")
         pybasedir = py.path.local(py.__file__).dirpath().dirpath()
+        genscript = py.path.local(genscript)
         main(pybasedir, outfile=genscript, infile=infile)
         raise SystemExit(0)
 
 def main(pybasedir, outfile, infile):
-    os.chdir(str(pybasedir))
     outfile = str(outfile)
     infile = str(infile)
+    assert os.path.isabs(outfile)
+    os.chdir(str(pybasedir))
     files = []
     for dirpath, dirnames, filenames in os.walk("py"):
         for f in filenames:

testing/plugin/test_pytest_genscript.py

@@ -7,9 +7,10 @@ def pytest_funcarg__standalone(request):
 class Standalone:
     def __init__(self, request):
         self.testdir = request.getfuncargvalue("testdir")
-        self.script = self.testdir.tmpdir.join("mypytest")
-        result = self.testdir.runpytest("--genscript=%s" % self.script)
+        script = "mypytest"
+        result = self.testdir.runpytest("--genscript=%s" % script)
         assert result.ret == 0
+        self.script = self.testdir.tmpdir.join(script)
         assert self.script.check()
 
     def run(self, anypython, testdir, *args):