Add more decorator tests

Signed-off-by: Ray Lehtiniemi <rayl@mail.com>

tests/roots/test-ext-viewcode/spam/mod1.py

@@ -2,6 +2,10 @@
 mod1
 """
 
+def decorator(f):
+    return f
+
+@decorator
 def func1(a, b):
     """
     this is func1
@@ -9,6 +13,7 @@ def func1(a, b):
     return a, b
 
 
+@decorator
 class Class1(object):
     """
     this is Class1

tests/roots/test-ext-viewcode/spam/mod2.py

@@ -2,6 +2,10 @@
 mod2
 """
 
+def decorator(f):
+    return f
+
+@decorator
 def func2(a, b):
     """
     this is func2
@@ -9,6 +13,7 @@ def func2(a, b):
     return a, b
 
 
+@decorator
 class Class2(object):
     """
     this is Class2

tests/test_ext_viewcode.py

@@ -30,6 +30,7 @@ def test_viewcode(app, status, warning):
     assert result.count('href="_modules/spam/mod2.html#func2"') == 2
     assert result.count('href="_modules/spam/mod1.html#Class1"') == 2
     assert result.count('href="_modules/spam/mod2.html#Class2"') == 2
+    assert result.count('@decorator') == 1
 
 
 @pytest.mark.sphinx(testroot='ext-viewcode', tags=['test_linkcode'])