[PY 3.8] test fixes for file closings, rawstrings

On a linux host (missing some things that may be on the Travis CI
setup), Py3.8a3 now shows 19 fails, 1048 pass, with 84 Warning: messages.

Signed-off-by: Mats Wichmann <mats@linux.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/test/duplicate-sources.py b/test/duplicate-sources.py
index 03b5686..3ad2928 100644
--- a/test/duplicate-sources.py
+++ b/test/duplicate-sources.py
@@ -35,10 +35,10 @@ test = TestSCons.TestSCons()
 
 test.write('SConstruct', """\
 def cat(target, source, env):
-    t = open(str(target[0]), 'wb')
-    for s in source:
-        t.write(open(str(s), 'rb').read())
-    t.close()
+    with open(str(target[0]), 'wb') as t:
+        for s in source:
+            with open(str(s), 'rb') as s:
+                t.write(s.read())
 env = Environment(BUILDERS = {'Cat' : Builder(action = cat)})
 env.Cat('out.txt', ['f1.in', 'f2.in', 'f1.in'])
 """)