--- /dev/null
+#!/usr/bin/env python
+#
+# __COPYRIGHT__
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+
+__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
+
+import os
+import sys
+import TestSCons
+
+test = TestSCons.TestSCons()
+
+test.write('SConstruct', """
+def bfunc(target, source, env):
+ import shutil
+ shutil.copyfile('f2.in', str(target[0]))
+
+B = Builder(action=bfunc)
+env = Environment(BUILDERS = { 'B' : B })
+env.B('f1.out', source='f1.in')
+env.AlwaysBuild('f1.out')
+""")
+
+test.write('f1.in', "f1.in\n")
+test.write('f2.in', "1")
+
+test.run(arguments = ".")
+test.fail_test(test.read('f1.out') != '1')
+
+test.write('f2.in', "2")
+test.run(arguments = ".")
+test.fail_test(test.read('f1.out') != '2')
+
+test.pass_test()