Adds the ability to depend on not a specific field value

HISTORY.rst

@@ -1,6 +1,9 @@
 Changelog
 ---------
 
+- Adds the ability to depend on not a specific field value.
+  [msom]
+
 0.11.2 (2016-05-11)
 ~~~~~~~~~~~~~~~~~~~
 

onegov/form/core.py

@@ -367,17 +367,19 @@ class FieldDependency(object):
 
     def __init__(self, field_id, choice):
         self.field_id = field_id
-        self.choice = choice
+        self.raw_choice = choice
+        self.invert = choice.startswith('!')
+        self.choice = choice[1:] if self.invert else choice
 
     def fulfilled(self, form, field):
-        return getattr(form, self.field_id).data == self.choice
+        return (getattr(form, self.field_id).data == self.choice) ^ self.invert
 
     def unfulfilled(self, form, field):
         return not self.fulfilled(form, field)
 
     @property
     def html_data(self):
-        return {'data-depends-on': '/'.join((self.field_id, self.choice))}
+        return {'data-depends-on': '/'.join((self.field_id, self.raw_choice))}
 
 
 def merge_forms(*forms):

onegov/form/tests/test_core.py

@@ -97,6 +97,12 @@ class TestForm(Form):
             depends_on=('switch', 'on')
         )
 
+        inverted = TimeField(
+            label="Inverted",
+            validators=[],
+            depends_on=('switch', '!on')
+        )
+
     request = DummyRequest({'switch': 'off'})
     form = TestForm(request.POST)
     assert form.validate()
@@ -133,6 +139,18 @@ class TestForm(Form):
     form = TestForm(request.POST)
     assert form.validate()
 
+    request = DummyRequest({'switch': 'on', 'inverted': '12:00'})
+    form = TestForm(request.POST)
+    assert not form.validate()
+
+    request = DummyRequest({'switch': 'off', 'inverted': '12:00'})
+    form = TestForm(request.POST)
+    assert form.validate()
+
+    request = DummyRequest({'switch': 'off', 'inverted': 'asdf'})
+    form = TestForm(request.POST)
+    assert not form.validate()
+
 
 def test_merge_forms():