Add script to run test suite with multiple python versions at once

diff --git a/tornado/test/run_pyversion_tests.py b/tornado/test/run_pyversion_tests.py
new file mode 100755 (executable)
index 0000000..8c4e967
--- /dev/null
+++ b/tornado/test/run_pyversion_tests.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+"""Runs the tornado test suite with all supported python interpreters."""
+
+import os
+import subprocess
+import sys
+
+INTERPRETERS = [
+    "python2.5",
+    "python2.6",
+    "python2.7",
+    "auto2to3",
+    "pypy",
+    ]
+
+def exists_on_path(filename):
+    for dir in os.environ["PATH"].split(":"):
+        if os.path.exists(os.path.join(dir, filename)):
+            return True
+    return False
+
+def main():
+    for interpreter in INTERPRETERS:
+        print "=================== %s =======================" % interpreter
+        if not exists_on_path(interpreter):
+            print "Interpreter not found, skipping..."
+            continue
+        args = [interpreter, "-m", "tornado.test.runtests"] + sys.argv[1:]
+        ret = subprocess.call(args)
+        if ret != 0:
+            print "Tests on %s failed with exit code %d" % (interpreter, ret)
+            sys.exit(ret)
+    print "All tests passed"
+
+if __name__ == "__main__":
+    main()