tests: Allow tests to pass against CPython 3.5.

All breaking changes going from 3.4 to 3.5 are contained in
basics/python34.py.

tests/basics/python34.py

@@ -0,0 +1,26 @@
+# tests that differ when running under Python 3.4 vs 3.5
+
+# from basics/fun_kwvarargs.py
+# test evaluation order of arguments (in 3.4 it's backwards, 3.5 it's fixed)
+def f4(*vargs, **kwargs):
+    print(vargs, kwargs)
+def print_ret(x):
+    print(x)
+    return x
+f4(*print_ret(['a', 'b']), kw_arg=print_ret(None))
+
+# from basics/syntaxerror.py
+# can't have multiple * or ** (in 3.5 we can)
+def test_syntax(code):
+    try:
+        exec(code)
+    except SyntaxError:
+        print("SyntaxError")
+test_syntax("f(*a, *b)")
+test_syntax("f(**a, **b)")
+
+# from basics/sys1.py
+# uPy prints version 3.4
+import sys
+print(sys.version[:3])
+print(sys.version_info[0], sys.version_info[1])