diff --git a/src/RestrictedPython/transformer.py b/src/RestrictedPython/transformer.py
index ba63321..f1b2629 100644
--- a/src/RestrictedPython/transformer.py
+++ b/src/RestrictedPython/transformer.py
@@ -631,27 +631,21 @@ def visit_UnaryOp(self, node):
         """
         UnaryOp (Unary Operations) is the overall element for:
         * Not --> which should be allowed
-        * UAdd
-        * USub
+        * UAdd --> Positive Number notation
+        * USub --> Negative Number notation
         """
         return self.node_contents_visit(node)
 
     def visit_UAdd(self, node):
-        """
-
-        """
-        self.not_allowed(node)
+        """Positive Numbers notation should be allowed."""
+        return self.node_contents_visit(node)
 
     def visit_USub(self, node):
-        """
-
-        """
-        self.not_allowed(node)
+        """Negativ Numbers notation should be allowed."""
+        return self.node_contents_visit(node)
 
     def visit_Not(self, node):
-        """
-        The Not Operator should be allowed.
-        """
+        """The Not Operator should be allowed."""
         return self.node_contents_visit(node)
 
     def visit_Invert(self, node):
@@ -661,9 +655,7 @@ def visit_Invert(self, node):
         self.not_allowed(node)
 
     def visit_BinOp(self, node):
-        """
-
-        """
+        """Binary Operations should be allowed."""
         return self.node_contents_visit(node)
 
     def visit_Add(self, node):
@@ -739,8 +731,9 @@ def visit_BitAnd(self, node):
         self.not_allowed(node)
 
     def visit_MatMult(self, node):
-        """
+        """Matrix Multiplication should not be allowed.
 
+        Matrix Multiplication (@) is a Python 3.5+ Feature.
         """
         self.not_allowed(node)
 
diff --git a/tests/transformer/test_global_local.py b/tests/transformer/test_global_local.py
new file mode 100644
index 0000000..2024892
--- /dev/null
+++ b/tests/transformer/test_global_local.py
@@ -0,0 +1,37 @@
+from tests import c_exec
+
+import pytest
+
+
+GLOBAL_EXAMPLE = """
+a = 1
+global a
+"""
+
+
+@pytest.mark.parametrize(*c_exec)
+def test_Global(c_exec):
+    result = c_exec(GLOBAL_EXAMPLE)
+    assert result.code is None
+    assert result.errors == (
+        'Line 3: Global statements are not allowed.',
+    )
+    assert result.warnings == []
+    assert result.used_names == {}
+
+
+NONLOCAL_EXAMPLE = """
+a = 1
+nonlocal a
+"""
+
+
+@pytest.mark.parametrize(*c_exec)
+def test_Nonlocal(c_exec):
+    result = c_exec(NONLOCAL_EXAMPLE)
+    assert result.code is None
+    assert result.errors == (
+        'Line 3: Nonlocal statements are not allowed.',
+    )
+    assert result.warnings == []
+    assert result.used_names == {}
diff --git a/tests/transformer/test_operators.py b/tests/transformer/test_operators.py
index cea0fac..f54c9bd 100644
--- a/tests/transformer/test_operators.py
+++ b/tests/transformer/test_operators.py
@@ -15,6 +15,9 @@ def test_Add(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result == 2
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_Sub(c_eval):
@@ -24,6 +27,9 @@ def test_Sub(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result == 1
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_Mult(c_eval):
@@ -33,6 +39,9 @@ def test_Mult(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result == 4
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_Div(c_eval):
@@ -42,12 +51,17 @@ def test_Div(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result == 5
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_Mod(c_eval):
-    result = c_eval('10 / 2')
-    assert result.code is not None
-    assert result.errors == ()
+    result = c_eval('10 % 2')
+    assert result.code is None
+    assert result.errors == (
+        'Line None: Mod statements are not allowed.',
+    )
     assert result.warnings == []
     assert result.used_names == {}
 
@@ -98,6 +112,9 @@ def test_Eq(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_NotEq(c_eval):
@@ -107,6 +124,9 @@ def test_NotEq(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_Gt(c_eval):
@@ -116,6 +136,9 @@ def test_Gt(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_Lt(c_eval):
@@ -125,6 +148,9 @@ def test_Lt(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_GtE(c_eval):
@@ -134,6 +160,9 @@ def test_GtE(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_LtE(c_eval):
@@ -143,6 +172,9 @@ def test_LtE(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 # Bool Operators
 
@@ -155,6 +187,9 @@ def test_Or(c_eval):
     assert result.warnings == []
     # assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_And(c_eval):
@@ -164,6 +199,21 @@ def test_And(c_eval):
     assert result.warnings == []
     # assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
+
+@pytest.mark.parametrize(*c_eval)
+def test_Not(c_eval):
+    result = c_eval('not False')
+    assert result.code is not None
+    assert result.errors == ()
+    assert result.warnings == []
+    # assert result.used_names == {}
+
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 # Bit wise Operators
 
@@ -244,6 +294,9 @@ def test_In(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_NotIn(c_eval):
@@ -253,6 +306,9 @@ def test_NotIn(c_eval):
     assert result.warnings == []
     assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 # Identity Operator
 
@@ -265,6 +321,9 @@ def test_Is(c_eval):
     assert result.warnings == []
     # assert result.used_names == {}
 
+    eval_result = eval(result.code)
+    assert eval_result is True
+
 
 @pytest.mark.parametrize(*c_eval)
 def test_NotIs(c_eval):
@@ -273,3 +332,33 @@ def test_NotIs(c_eval):
     assert result.errors == ()
     assert result.warnings == []
     # assert result.used_names == {}
+
+    eval_result = eval(result.code)
+    assert eval_result is True
+
+
+# Unary Operators
+
+
+@pytest.mark.parametrize(*c_eval)
+def test_UAdd(c_eval):
+    result = c_eval('+1')
+    assert result.code is not None
+    assert result.errors == ()
+    assert result.warnings == []
+    # assert result.used_names == {}
+
+    eval_result = eval(result.code)
+    assert eval_result == 1
+
+
+@pytest.mark.parametrize(*c_eval)
+def test_USub(c_eval):
+    result = c_eval('-1')
+    assert result.code is not None
+    assert result.errors == ()
+    assert result.warnings == []
+    # assert result.used_names == {}
+
+    eval_result = eval(result.code)
+    assert eval_result == -1