--- a/python/mozbuild/mozbuild/test/configure/test_checks_configure.py
+++ b/python/mozbuild/mozbuild/test/configure/test_checks_configure.py
@@ -10,16 +10,17 @@ import textwrap
 import unittest
 
 from mozunit import main
 
 from mozbuild.configure import (
     ConfigureError,
     ConfigureSandbox,
 )
+from mozbuild.util import exec_
 
 from buildconfig import topsrcdir
 
 
 class FindProgramSandbox(ConfigureSandbox):
     def __init__(self, *args, **kwargs):
         super(FindProgramSandbox, self).__init__(*args, **kwargs)
 
@@ -53,17 +54,17 @@ class FindProgramSandbox(ConfigureSandbo
 
 class TestChecksConfigure(unittest.TestCase):
     def test_checking(self):
         out = StringIO()
         sandbox = FindProgramSandbox({}, stdout=out, stderr=out)
         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
         '''), sandbox)
 
         foo = sandbox['foo']
 
         foo(True)
@@ -83,17 +84,17 @@ class TestChecksConfigure(unittest.TestC
 
         out.truncate(0)
         data = ['foo', 'bar']
         foo(data)
         self.assertEqual(out.getvalue(), 'checking for a thing... %r\n' % data)
 
         # 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
         '''), sandbox)
 
         foo = sandbox['foo']
 
         out.truncate(0)
@@ -112,17 +113,17 @@ class TestChecksConfigure(unittest.TestC
         foo('foo')
         self.assertEqual(out.getvalue(), 'checking for a thing... foo\n')
 
         out.truncate(0)
         data = ['foo', 'bar']
         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'
                 if isinstance(x, (str, bool, int)):
                     return x
                 return ' '.join(x)
 
             @checking('for a thing', munge)
@@ -158,17 +159,17 @@ class TestChecksConfigure(unittest.TestC
         out = StringIO()
         sandbox = FindProgramSandbox(config, environ, [prog] + args, out, out)
         base_dir = os.path.join(topsrcdir, 'build', 'moz.configure')
         sandbox.include_file(os.path.join(base_dir, 'util.configure'))
         sandbox.include_file(os.path.join(base_dir, 'checks.configure'))
 
         status = 0
         try:
-            exec(command, sandbox)
+            exec_(command, sandbox)
             sandbox.run()
         except SystemExit as e:
             status = e.code
 
         return config, out.getvalue(), status
 
     def test_check_prog(self):
         config, out, status = self.get_result(

--- a/python/mozbuild/mozbuild/test/configure/test_configure.py
+++ b/python/mozbuild/mozbuild/test/configure/test_configure.py
@@ -19,16 +19,17 @@ from mozbuild.configure.options import (
     InvalidOptionError,
     NegativeOptionValue,
     PositiveOptionValue,
 )
 from mozbuild.configure import (
     ConfigureError,
     ConfigureSandbox,
 )
+from mozbuild.util import exec_
 
 import mozpack.path as mozpath
 
 test_data_path = mozpath.abspath(mozpath.dirname(__file__))
 test_data_path = mozpath.join(test_data_path, 'data')
 
 
 class TestConfigure(unittest.TestCase):
@@ -239,100 +240,100 @@ class TestConfigure(unittest.TestCase):
         self.assertNotIn('CFLAGS', config)
 
     def test_imports(self):
         config = {}
         out = StringIO()
         sandbox = ConfigureSandbox(config, {}, [], out, out)
 
         with self.assertRaises(ImportError):
-            exec(textwrap.dedent('''
+            exec_(textwrap.dedent('''
                 @template
                 def foo():
                     import sys
                 foo()'''),
                 sandbox
             )
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports('sys')
             def foo():
                 return sys'''),
             sandbox
         )
 
         self.assertIs(sandbox['foo'](), sys)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_from='os', _import='path')
             def foo():
                 return path'''),
             sandbox
         )
 
         self.assertIs(sandbox['foo'](), os.path)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_from='os', _import='path', _as='os_path')
             def foo():
                 return os_path'''),
             sandbox
         )
 
         self.assertIs(sandbox['foo'](), os.path)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports('__builtin__')
             def foo():
                 return __builtin__'''),
             sandbox
         )
 
         import __builtin__
         self.assertIs(sandbox['foo'](), __builtin__)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_from='__builtin__', _import='open')
             def foo():
                 return open('%s')''' % os.devnull),
             sandbox
         )
 
         f = sandbox['foo']()
         self.assertEquals(f.name, os.devnull)
         f.close()
 
         # This unlocks the sandbox
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_import='__builtin__', _as='__builtins__')
             def foo():
                 import sys
                 return sys'''),
             sandbox
         )
 
         self.assertIs(sandbox['foo'](), sys)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports('__sandbox__')
             def foo():
                 return __sandbox__'''),
             sandbox
         )
 
         self.assertIs(sandbox['foo'](), sandbox)
 
-        exec(textwrap.dedent('''
+        exec_(textwrap.dedent('''
             @template
             @imports(_import='__sandbox__', _as='s')
             def foo():
                 return s'''),
             sandbox
         )
 
         self.assertIs(sandbox['foo'](), sandbox)