Batching in ZSQLMethod test is broken

[Bug Importer]

When using "Test" tab for ZSQLMethod which has some parameters
only first 20 results are shown correctly.
'(Next 20 results)' link is broken. It leads to page that says:

Error, exceptions.NameError: name 'param_name' is not defined
SQL used:
Could not render the query template!

This is because of not passing query parameters in the '(Next 20 results)' link. There is additional, unnecessary 'query' parameter in this link that is always empty:

http://host:8080/folder/my_method/manage_test?query_start=21&query=''

[Victor Safronovich (suvit)]

the parameter 'query' is not empty, it equals to "''".

[Maciej Wisniowski (pigletto)]

Uploaded: ZSQLTestHotfix.tar.gz

I've found that changing two lines in file:
[ZOPE_HOME]/lib/python/Shared/DC/ZRDB/dtml/customDefaultReport.dtml

from:
<a href="&dtml-URL;?query_start=&dtml-previous-sequence-start-number;&query=<dtml-var query url_quote missing=''>">
(...)
<a href="&dtml-URL;?query_start=&dtml-next-sequence-start-number;&query=<dtml-var query url_quote missing=''>">

to:
<a href="&dtml-URL;<dtml-var sequence-query missing=''>query_start=&dtml-previous-sequence-start-number;">
(...)
<a href="&dtml-URL;<dtml-var sequence-query missing=''>query_start=&dtml-next-sequence-start-number;">

seems to solve this problem.

[Victor Safronovich (suvit)]

using missing='' is wrong, because it renders as "''", but missing="" renders as empty string ""

[Colin Watson (cjwatson)]

The products.zsqlmethods project on Launchpad has been archived at the request of the Zope developers (see https://answers.launchpad.net/launchpad/+question/683589 and https://answers.launchpad.net/launchpad/+question/685285). If this bug is still relevant, please refile it at https://github.com/zopefoundation/products.zsqlmethods.