guard against tests trying to import this

--HG--
branch : trunk

py/_testing/check_compile.py

@@ -1,10 +1,13 @@
 import sys
 
-fn = sys.argv[1]
-print("Testing %s" % (fn,))
-fp = open(fn, "rb")
-try:
-    source = fp.read()
-finally:
-    fp.close()
-compile(source, fn, "exec")
+def main(fn):
+    print("Testing %s" % (fn,))
+    fp = open(fn, "rb")
+    try:
+        source = fp.read()
+    finally:
+        fp.close()
+    compile(source, fn, "exec")
+
+if __name__ == "__main__":
+    main(sys.argv[1])