tests/basics: Add tests for variable annotations.

tests/basics/annotate_var.py

@@ -0,0 +1,25 @@
+# test PEP 526, varible annotations
+
+x: int
+print("x" in globals())
+
+x: int = 1
+print(x)
+
+t: tuple = 1, 2
+print(t)
+
+# a pure annotation in a function makes that variable local
+def f():
+    x: int
+    try:
+        print(x)
+    except NameError:
+        print("NameError")
+f()
+
+# here, "x" should remain a global
+def f():
+    x.y: int
+    print(x)
+f()

tests/basics/annotate_var.py.exp

@@ -0,0 +1,5 @@
+False
+1
+(1, 2)
+NameError
+1

tests/run-tests

@@ -414,6 +414,7 @@ def run_tests(pyb, tests, args, base_path="."):
         skip_tests.update({'basics/%s.py' % t for t in 'gen_yield_from_close generator_name'.split()}) # require raise_varargs, generator name
         skip_tests.update({'basics/async_%s.py' % t for t in 'with with2 with_break with_return'.split()}) # require async_with
         skip_tests.update({'basics/%s.py' % t for t in 'try_reraise try_reraise2'.split()}) # require raise_varargs
+        skip_tests.add('basics/annotate_var.py') # requires checking for unbound local
         skip_tests.add('basics/del_deref.py') # requires checking for unbound local
         skip_tests.add('basics/del_local.py') # requires checking for unbound local
         skip_tests.add('basics/exception_chain.py') # raise from is not supported