Cleanups in tests and in framework

* Some Py2/Py3 compat blocks were simplified to Py3 only
* some sequences of define-cleaup-function + atexit.register
  were changed to use the decorator (this works if func needs to
  take no arguments)
* Lightly update a bunch of docstrings in TestCmd, and reformat
  a few places, towards the style we're generally using now.
* call_python() in TestCmdTests was modernized to use subprocess.run

Signed-off-by: Mats Wichmann <[email protected]>

Author: mwichmann

test/SConscript/SConscript.py

@@ -34,6 +34,7 @@
 test.write('SConstruct', """\
 import os
 import foo
+from collections import UserList
 
 assert foo.foo == 4
 
@@ -71,10 +72,6 @@
 
 SConscript('SConscript5')
 
-try:
-    from collections import UserList
-except ImportError:
-    from UserList import UserList
 x7 = "SConstruct x7"
 x8 = "SConstruct x8"
 x9 = SConscript('SConscript6', UserList(["x7", "x8"]))

test/option/option_profile.py

@@ -24,18 +24,9 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
-import sys
-
-# TODO: Fixup StringIO usage when Py2.7 is dropped.
-# cheat a little bit: io.StringIO is "preferred" in Py2.7
-# since it forces you to be explicit about strings (it is unicode-only)
-# It's easier to use the unaware version. Which also doesn't come
-# with a context manager, so use contextlib.closing
-try:
-    from cStringIO import StringIO
-except ImportError:
-    from io import StringIO
 import contextlib
+import sys
+from io import StringIO
 
 import TestSCons
 

test/redirection.py

@@ -32,7 +32,6 @@
 
 test.write('cat.py', r"""
 import sys
-PY3K = sys.version_info >= (3, 0)
 
 # write binary to stdout
 if sys.platform == "win32":
@@ -45,17 +44,10 @@
     with open(sys.argv[1], 'rb') as f:
         indata = f.read()
 except IndexError:
-    if PY3K:
-        source = sys.stdin.buffer
-    else:
-        source = sys.stdin
+    source = sys.stdin
     indata = source.read()
     
-if PY3K:
-    sys.stdout.buffer.write(indata)
-else:
-    sys.stdout.write(indata)
-
+sys.stdout.buffer.write(indata)
 sys.exit(0)
 """)