hr_timesheet_workflow.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>

        <!-- Workflow definition -->

        <record id="wkf_timesheet" model="workflow">
            <field name="name">hr_timesheet_sheet.sheet</field>
            <field name="osv">hr_timesheet_sheet.sheet</field>
            <field name="on_create">True</field>
        </record>

        <record id="act_new" model="workflow.activity">
            <field name="wkf_id" ref="wkf_timesheet"/>
            <field name="name">new</field>
            <field name="kind">function</field>
            <field name="action">write({'state':'new'})</field>
            <field name="flow_start">True</field>
        </record>
        <record id="act_draft" model="workflow.activity">
            <field name="wkf_id" ref="wkf_timesheet"/>
            <field name="name">draft</field>
            <field name="kind">function</field>
            <field name="action">write({'state':'draft'})</field>
        </record>
        <record id="act_confirm" model="workflow.activity">
            <field name="wkf_id" ref="wkf_timesheet"/>
            <field name="name">confirm</field>
            <field name="kind">function</field>
            <field name="action">write({'state':'confirm'})</field>
        </record>
        <record id="act_done" model="workflow.activity">
            <field name="wkf_id" ref="wkf_timesheet"/>
            <field name="name">done</field>
            <field name="kind">function</field>
            <field name="action">write({'state':'done'})</field>
            <field name="flow_stop">True</field>
        </record>

        <record id="t0" model="workflow.transition">
            <field name="act_from" ref="act_new"/>
            <field name="act_to" ref="act_draft"/>
            <field name="group_id" ref="base.group_user"/>
        </record>
        <record id="t1" model="workflow.transition">
            <field name="act_from" ref="act_draft"/>
            <field name="act_to" ref="act_confirm"/>
            <field name="signal">confirm</field>
            <field name="group_id" ref="base.group_user"/>
        </record>
        <record id="t2" model="workflow.transition">
            <field name="act_from" ref="act_confirm"/>
            <field name="act_to" ref="act_done"/>
            <field name="signal">done</field>
            <field name="group_id" ref="base.group_hr_user"/>
        </record>
        <record id="t3" model="workflow.transition">
            <field name="act_from" ref="act_confirm"/>
            <field name="act_to" ref="act_draft"/>
            <field name="signal">cancel</field>
            <field name="group_id" ref="base.group_hr_user"/>
        </record>
    </data>
</openerp>