find_entry_by_attr() should fail if multiple entries are found

It will only ever return one entry so if more than one are found
then we raise an exception. This is most easily seen in the host
plugin where we search on the server shortname which can be the
same across sub-domains (e.g. foo.example.com &
foo.lab.example.com).

https://fedorahosted.org/freeipa/ticket/1388

tests/test_xmlrpc/test_host_plugin.py

@@ -39,6 +39,8 @@ dn2 = u'fqdn=%s,cn=computers,cn=accounts,%s' % (fqdn2, api.env.basedn)
 fqdn3 = u'testhost2.%s' % api.env.domain
 short3 = u'testhost2'
 dn3 = u'fqdn=%s,cn=computers,cn=accounts,%s' % (fqdn3, api.env.basedn)
+fqdn4 = u'testhost2.lab.%s' % api.env.domain
+dn4 = u'fqdn=%s,cn=computers,cn=accounts,%s' % (fqdn4, api.env.basedn)
 
 # We can use the same cert we generated for the service tests
 fd = open('tests/test_xmlrpc/service.crt', 'r')
@@ -53,6 +55,7 @@ class test_host(Declarative):
         ('host_del', [fqdn1], {}),
         ('host_del', [fqdn2], {}),
         ('host_del', [fqdn3], {}),
+        ('host_del', [fqdn4], {}),
         ('service_del', [service1], {}),
     ]
 
@@ -294,6 +297,32 @@ class test_host(Declarative):
         ),
 
 
+        dict(
+            desc='Create %r' % fqdn4,
+            command=('host_add', [fqdn4],
+                dict(
+                    description=u'Test host 4',
+                    l=u'Undisclosed location 4',
+                    force=True,
+                ),
+            ),
+            expected=dict(
+                value=fqdn4,
+                summary=u'Added host "%s"' % fqdn4,
+                result=dict(
+                    dn=dn4,
+                    fqdn=[fqdn4],
+                    description=[u'Test host 4'],
+                    l=[u'Undisclosed location 4'],
+                    krbprincipalname=[u'host/%s@%s' % (fqdn4, api.env.realm)],
+                    objectclass=objectclasses.host,
+                    ipauniqueid=[fuzzy_uuid],
+                    managedby_host=[u'%s' % fqdn4],
+                ),
+            ),
+        ),
+
+
         dict(
             desc='Add managedby_host %r to %r' % (fqdn1, fqdn3),
             command=('host_add_managedby', [fqdn3],
@@ -363,6 +392,12 @@ class test_host(Declarative):
         ),
 
 
+        dict(
+            desc='Show a host with multiple matches %s' % short3,
+            command=('host_show', [short3], {}),
+            expected=errors.SingleMatchExpected(found=2),
+        ),
+
 
         dict(
             desc='Try to rename %r' % fqdn1,