S3 Fuzzer: Handle null choices

Sometimes you might want to have your current node terminate the descent or
set something to the empty string.

request_decision_graph.yml

@@ -5,7 +5,7 @@ start:
 
 bucket:
     set:
-        urlpath: '/{bucket}'
+        urlpath: /{bucket}
     choice:
         - bucket_get
         - bucket_put
@@ -13,24 +13,10 @@ bucket:
 
 bucket_delete:
     set:
-        method: 'DELETE'
-    choice:
-        - delete_bucket
-        - delete_bucket_policy
-        - delete_bucket_website
-
-delete_bucket:
-    set:
-        query: null
-    choice: []
-
-delete_bucket_policy:
-    set:
-        query: 'policy'
-    choice: []
-
-delete_bucket_website:
-    set:
-        query: 'website'
+        method: DELETE
+        query:
+            - null
+            - policy
+            - website
     choice: []
 

s3tests/functional/test_fuzzer.py

@@ -65,6 +65,10 @@ def build_graph():
         },
         'choices': ['leaf']
     }
+    graph['nonexistant_child_node'] = {
+        'set': {},
+        'choices': ['leafy_greens']
+    }
     graph['weighted_node'] = {
         'set': {
             'k1': [
@@ -79,6 +83,14 @@ def build_graph():
             '1 baz'
         ]
     }
+    graph['null_choice_node'] = {
+        'set': {},
+        'choices': [None]
+    }
+    graph['weighted_null_choice_node'] = {
+        'set': {},
+        'choices': ['3 null']
+    }
     return graph
 
 
@@ -114,6 +126,12 @@ def test_descend_bad_node():
     assert_raises(KeyError, descend_graph, graph, 'bad_node', prng)
 
 
+def test_descend_nonexistant_child():
+    graph = build_graph()
+    prng = random.Random(1)
+    assert_raises(KeyError, descend_graph, graph, 'nonexistant_child_node', prng)
+
+
 def test_SpecialVariables_dict():
     prng = random.Random(1)
     testdict = {'foo': 'bar'}
@@ -128,6 +146,7 @@ def test_SpecialVariables_binary():
 
     eq(tester['random 10-15 binary'], '\xdfj\xf1\xd80>a\xcd\xc4\xbb')
 
+
 def test_assemble_decision():
     graph = build_graph()
     prng = random.Random(1)
@@ -140,6 +159,7 @@ def test_assemble_decision():
     eq(decision['path'], '/{bucket_readable}')
     assert_raises(KeyError, lambda x: decision[x], 'key3')
 
+
 def test_expand_key():
     prng = random.Random(1)
     test_decision = {
@@ -158,6 +178,7 @@ def test_expand_key():
     eq(dbl_indirect, 'value1')
     eq(randkey, 'value-[/pNI$;92@')
 
+
 def test_expand_loop():
     prng = random.Random(1)
     test_decision = {
@@ -167,6 +188,7 @@ def test_expand_loop():
     decision = SpecialVariables(test_decision, prng)
     assert_raises(RuntimeError, expand_key, decision, test_decision['key1'])
 
+
 def test_expand_decision():
     graph = build_graph()
     prng = random.Random(1)
@@ -182,6 +204,7 @@ def test_expand_decision():
     eq(request['randkey'], 'value-cx+*~G@&uW_[OW3')
     assert_raises(KeyError, lambda x: decision[x], 'key3')
 
+
 def test_weighted_choices():
     graph = build_graph()
     prng = random.Random(1)
@@ -201,6 +224,31 @@ def test_weighted_choices():
     nose.tools.assert_almost_equal(bar_percentage, 0.50, 1)
     nose.tools.assert_almost_equal(baz_percentage, 0.25, 1)
 
+
+def test_null_choices():
+    graph = build_graph()
+    prng = random.Random(1)
+    choice = make_choice(graph['null_choice_node']['choices'], prng)
+
+    eq(choice, '')
+
+
+def test_weighted_null_choices():
+    graph = build_graph()
+    prng = random.Random(1)
+    choice = make_choice(graph['weighted_null_choice_node']['choices'], prng)
+
+    eq(choice, '')
+
+
+def test_null_child():
+    graph = build_graph()
+    prng = random.Random(1)
+    decision = descend_graph(graph, 'null_choice_node', prng)
+
+    eq(decision, {})
+
+
 def test_weighted_set():
     graph = build_graph()
     prng = random.Random(1)
@@ -220,6 +268,7 @@ def test_weighted_set():
     nose.tools.assert_almost_equal(bar_percentage, 0.50, 1)
     nose.tools.assert_almost_equal(baz_percentage, 0.25, 1)
 
+
 def test_header_presence():
     graph = build_graph()
     prng = random.Random(1)
@@ -241,7 +290,6 @@ def test_header_presence():
     nose.tools.assert_true(next(c2))
 
 
-
 def test_header_expansion():
     graph = build_graph()
     prng = random.Random(1)

s3tests/fuzz_headers.py

@@ -29,7 +29,10 @@ def descend_graph(decision_graph, node_name, prng):
 
     try:
         choice = make_choice(node['choices'], prng)
-        decision = descend_graph(decision_graph, choice, prng)
+        if choice == '':
+            decision = {}
+        else:
+            decision = descend_graph(decision_graph, choice, prng)
     except IndexError:
         decision = {}
 
@@ -72,6 +75,9 @@ def make_choice(choices, prng):
         return choices
     weighted_choices = []
     for option in choices:
+        if option is None:
+            weighted_choices.append('')
+            continue
         fields = option.split(None, 1)
         if len(fields) == 1:
             weight = 1
@@ -79,6 +85,8 @@ def make_choice(choices, prng):
         else:
             weight = int(fields[0])
             value = fields[1]
+            if value == 'null' or value == 'None':
+                value = ''
         for _ in xrange(weight):
             weighted_choices.append(value)