Bug 1266343 - Use mozbuild.util.exec_ in the various configure tests. r=chmanchester

Because some older python 2.7 versions throw bogus errors when using the
exec statement as a function, use the function we added in bug 1264831
everywhere we use exec in the various configure tests. It doesn't take
much to trigger them, and the following changes ends up doing exactly
that.

python/mozbuild/mozbuild/test/configure/test_checks_configure.py

@@ -15,6 +15,7 @@ from mozbuild.configure import (
     ConfigureError,
     ConfigureSandbox,
 )
+from mozbuild.util import exec_
 
 from buildconfig import topsrcdir
 
@@ -58,7 +59,7 @@ class TestChecksConfigure(unittest.TestCase):
         base_dir = os.path.join(topsrcdir, 'build', 'moz.configure')
         sandbox.include_file(os.path.join(base_dir, 'checks.configure'))
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @checking('for a thing')
             def foo(value):
                 return value
@@ -88,7 +89,7 @@ class TestChecksConfigure(unittest.TestCase):
 
         # When the function given to checking does nothing interesting, the
         # behavior is not altered
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @checking('for a thing', lambda x: x)
             def foo(value):
                 return value
@@ -117,7 +118,7 @@ class TestChecksConfigure(unittest.TestCase):
         foo(data)
         self.assertEqual(out.getvalue(), 'checking for a thing... %r\n' % data)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             def munge(x):
                 if not x:
                     return 'not found'
@@ -163,7 +164,7 @@ class TestChecksConfigure(unittest.TestCase):
 
         status = 0
         try:
-            exec(command, sandbox)
+            exec_(command, sandbox)
             sandbox.run()
         except SystemExit as e:
             status = e.code

python/mozbuild/mozbuild/test/configure/test_configure.py

@@ -24,6 +24,7 @@ from mozbuild.configure import (
     ConfigureError,
     ConfigureSandbox,
 )
+from mozbuild.util import exec_
 
 import mozpack.path as mozpath
 
@@ -244,7 +245,7 @@ class TestConfigure(unittest.TestCase):
         sandbox = ConfigureSandbox(config, {}, [], out, out)
 
         with self.assertRaises(ImportError):
-            exec(textwrap.dedent('''
+            exec_(textwrap.dedent('''
                 @template
                 def foo():
                     import sys
@@ -252,7 +253,7 @@ class TestConfigure(unittest.TestCase):
                 sandbox
             )
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports('sys')
             def foo():
@@ -262,7 +263,7 @@ class TestConfigure(unittest.TestCase):
 
         self.assertIs(sandbox['foo'](), sys)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_from='os', _import='path')
             def foo():
@@ -272,7 +273,7 @@ class TestConfigure(unittest.TestCase):
 
         self.assertIs(sandbox['foo'](), os.path)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_from='os', _import='path', _as='os_path')
             def foo():
@@ -282,7 +283,7 @@ class TestConfigure(unittest.TestCase):
 
         self.assertIs(sandbox['foo'](), os.path)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports('__builtin__')
             def foo():
@@ -293,7 +294,7 @@ class TestConfigure(unittest.TestCase):
         import __builtin__
         self.assertIs(sandbox['foo'](), __builtin__)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_from='__builtin__', _import='open')
             def foo():
@@ -306,7 +307,7 @@ class TestConfigure(unittest.TestCase):
         f.close()
 
         # This unlocks the sandbox
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_import='__builtin__', _as='__builtins__')
             def foo():
@@ -317,7 +318,7 @@ class TestConfigure(unittest.TestCase):
 
         self.assertIs(sandbox['foo'](), sys)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports('__sandbox__')
             def foo():
@@ -327,7 +328,7 @@ class TestConfigure(unittest.TestCase):
 
         self.assertIs(sandbox['foo'](), sandbox)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_import='__sandbox__', _as='s')
             def foo():