[FIX] qweb: fix t-if and t-else and add test

Can not use remove with the loop for in (in _compile_directive_content)

addons/web/static/lib/qweb/qweb-test-conditionals.xml

@@ -15,4 +15,18 @@
         <t t-if="condition">fail</t>
     </t>
     <result id="boolean-value-condition-missing"/>
+
+    <t t-name="boolean-value-condition-else">
+        <div><span>begin</span><t t-if="condition">ok</t>
+        <t t-else="t-else">ok-else</t><span>end</span></div>
+    </t>
+    <params id="boolean-value-condition-else">{"condition": true}</params>
+    <result id="boolean-value-condition-else"><div><span>begin</span>ok<span>end</span></div></result>
+
+    <t t-name="boolean-value-condition-false-else">
+        <div><span>begin</span><t t-if="condition">fail</t>
+        <t t-else="t-else">fail-else</t><span>end</span></div>
+    </t>
+    <params id="boolean-value-condition-false-else">{"condition": false}</params>
+    <result id="boolean-value-condition-false-else"><div><span>begin</span>fail-else<span>end</span></div></result>
 </templates>

openerp/addons/base/ir/ir_qweb/qweb.py

@@ -977,10 +977,13 @@ class QWeb(object):
         return body
 
     def _compile_directive_else(self, el, options):
+        if el.attrib.pop('t-else') == '_t_skip_else_':
+            return []
         if not options.pop('t_if', None):
             raise ValueError("t-else directive must be preceded by t-if directive")
-        el.attrib.pop('t-else')
-        return self._compile_directives(el, options)
+        compiled = self._compile_directives(el, options)
+        el.attrib['t-else'] = '_t_skip_else_'
+        return compiled
 
     def _compile_directive_if(self, el, options):
         orelse = []
@@ -990,7 +993,6 @@ class QWeb(object):
                 raise ValueError("Unexpected non-whitespace characters between t-if and t-else directives")
             el.tail = None
             orelse = self._compile_node(next_el, dict(options, t_if=True))
-            next_el.getparent().remove(next_el)
         return [
             # if $t-if:
             #    next tag directive

openerp/addons/base/tests/test_qweb.py

@@ -8,6 +8,7 @@ import os.path
 import re
 
 from lxml import etree
+from itertools import chain
 
 from odoo.modules import get_module_resource
 from odoo.tests.common import TransactionCase
@@ -85,6 +86,12 @@ class FileSystemLoader(object):
                 arch = etree.tostring(root, encoding='utf-8', xml_declaration=True)
                 return arch
 
+def stringify_children(node):
+    parts = ([node.text] +
+            list(chain(*([c.text, etree.tostring(c), c.tail] for c in node.getchildren() if not isinstance(c, etree._Comment)))) +
+            [node.tail])
+    # filter removes possible Nones in texts and tails
+    return ''.join(filter(None, parts))
 
 class TestQWeb(TransactionCase):
     matcher = re.compile(r'^qweb-test-(.*)\.xml$')
@@ -125,7 +132,7 @@ class TestQWeb(TransactionCase):
             # so output is predictable & repeatable
             params = {} if param is None else json.loads(param.text, object_pairs_hook=collections.OrderedDict)
 
-            result = doc.find('result[@id="{}"]'.format(template)).text
+            result = stringify_children(doc.find('result[@id="{}"]'.format(template)))
             self.assertEqual(
                 qweb.render(template, values=params, load=loader).strip().encode('utf-8'),
                 (result or u'').strip().encode('utf-8'),