Merge pull request #89 from cjwatson/strict-displayValue-setter

Add error checking to displayValue setters

CHANGES.rst

@@ -9,6 +9,14 @@ CHANGES
   ``browser.post`` is called directly.  See `issue 87
   <https://github.com/zopefoundation/zope.testbrowser/issues/87>`_.
 
+- Add error checking to the setters for ``ListControl.displayValue`` and
+  ``CheckboxListControl.displayValue``: in line with the old
+  ``mechanize``-based implementation, these will now raise
+  ``ItemNotFoundError`` if any of the given values are not found, or
+  ``ItemCountError`` on trying to set more than one value on a single-valued
+  control.  See `issue 44
+  <https://github.com/zopefoundation/zope.testbrowser/issues/44>`_.
+
 
 5.5.0 (2019-11-11)
 ------------------

docs/narrative.rst

@@ -844,6 +844,10 @@ These fields have four other attributes and an additional method:
     ['Un', 'Deux']
     >>> ctrl.value
     ['1', '2']
+    >>> ctrl.displayValue = ['Quatre']
+    Traceback (most recent call last):
+    ...
+    ItemNotFoundError: Quatre
 
 - 'controls' gives you a list of the subcontrol objects in the control
   (subcontrols are discussed below).
@@ -1074,6 +1078,14 @@ Selection Control (Single-Valued)
     ['Third']
     >>> ctrl.value
     ['3']
+    >>> ctrl.displayValue = ['Quatre']
+    Traceback (most recent call last):
+    ...
+    ItemNotFoundError: Quatre
+    >>> ctrl.displayValue = ['Uno', 'Dos']
+    Traceback (most recent call last):
+    ...
+    ItemCountError: single selection list, must set sequence of length 0 or 1
 
 Selection Control (Multi-Valued)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1124,6 +1136,10 @@ Checkbox Control (Single-Valued; Unvalued)
     >>> browser.getControl(
     ...     name='single-disabled-unvalued-checkbox-value').disabled
     True
+    >>> ctrl.displayValue = ['Nonsense']
+    Traceback (most recent call last):
+    ...
+    ItemNotFoundError: Nonsense
 
 Checkbox Control (Single-Valued, Valued)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1166,6 +1182,10 @@ Checkbox Control (Single-Valued, Valued)
     False
     >>> ctrl.displayValue
     []
+    >>> ctrl.displayValue = ['Nonsense']
+    Traceback (most recent call last):
+    ...
+    ItemNotFoundError: Nonsense
 
   - Checkbox Control (Multi-Valued)
 
@@ -1209,6 +1229,10 @@ Checkbox Control (Single-Valued, Valued)
     >>> browser.getControl('Three').selected = False
     >>> ctrl.value
     []
+    >>> ctrl.displayValue = ['Four']
+    Traceback (most recent call last):
+    ...
+    ItemNotFoundError: Four
 
 Radio Control
 ~~~~~~~~~~~~~
@@ -1271,6 +1295,14 @@ This is just unit testing:
     ['1']
     >>> ctrl.displayValue
     ['Ein']
+    >>> ctrl.displayValue = ['Vier']
+    Traceback (most recent call last):
+    ...
+    ItemNotFoundError: Vier
+    >>> ctrl.displayValue = ['Ein', 'Zwei']
+    Traceback (most recent call last):
+    ...
+    ItemCountError: single selection list, must set sequence of length 0 or 1
 
 The radio control subcontrols were illustrated above.
 

src/zope/testbrowser/browser.py

@@ -877,12 +877,19 @@ def displayValue(self, value):
 
         if isinstance(value, string_types):
             value = [value]
+        if not self.multiple and len(value) > 1:
+            raise ItemCountError(
+                "single selection list, must set sequence of length 0 or 1")
         values = []
+        found = set()
         for key, titles in self._getOptions():
-            if any(v in t
-                   for t in titles
-                   for v in value):
+            matches = set(v for t in titles for v in value if v in t)
+            if matches:
                 values.append(key)
+                found.update(matches)
+        for v in value:
+            if v not in found:
+                raise ItemNotFoundError(v)
         self.value = values
 
     @property
@@ -999,8 +1006,14 @@ def displayValue(self):
 
     @displayValue.setter
     def displayValue(self, value):
+        found = set()
         for c in self.controls:
-            c.selected = any(v in c.labels for v in value)
+            matches = set(v for v in value if v in c.labels)
+            c.selected = bool(matches)
+            found.update(matches)
+        for v in value:
+            if v not in found:
+                raise ItemNotFoundError(v)
 
     @property
     def multiple(self):
@@ -1489,3 +1502,11 @@ class BrowserStateError(Exception):
 
 class LinkNotFoundError(IndexError):
     pass
+
+
+class ItemCountError(ValueError):
+    pass
+
+
+class ItemNotFoundError(ValueError):
+    pass

src/zope/testbrowser/tests/test_browser.py

@@ -20,7 +20,11 @@
 import doctest
 import unittest
 
-from zope.testbrowser.browser import Browser
+from zope.testbrowser.browser import (
+    Browser,
+    ItemCountError,
+    ItemNotFoundError,
+)
 import zope.testbrowser.tests.helper
 
 
@@ -131,6 +135,18 @@ def test_displayValue_set_empty_value(self):
         self.control.displayValue = []
         self.assertEqual(self.control.displayValue, [])
 
+    def test_displayValue_set_missing_value(self):
+        self.assertEqual(self.control.displayValue, ['Turn'])
+        self.assertRaises(
+            ItemNotFoundError, setattr, self.control, 'displayValue',
+            ['Missing'])
+
+    def test_displayValue_set_too_many_values(self):
+        self.assertEqual(self.control.displayValue, ['Turn'])
+        self.assertRaises(
+            ItemCountError, setattr, self.control, 'displayValue',
+            ['Turn', 'Alternative'])
+
 
 class TestMechRepr(unittest.TestCase):
     """Testing ..browser.*.mechRepr()."""