Index: openacs-4/packages/acs-automated-testing/tcl/aa-test-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-automated-testing/tcl/aa-test-procs.tcl,v
diff -u -r1.79.2.8 -r1.79.2.9
--- openacs-4/packages/acs-automated-testing/tcl/aa-test-procs.tcl	9 Apr 2019 14:30:49 -0000	1.79.2.8
+++ openacs-4/packages/acs-automated-testing/tcl/aa-test-procs.tcl	16 Apr 2019 09:27:24 -0000	1.79.2.9
@@ -1115,6 +1115,58 @@
 
 namespace eval acs::test {
 
+    ad_proc -public ::acs::test::require_package_instance {
+        -package_key:required
+        {-instance_name ""}
+        {-empty:boolean}
+    } {
+        Returns a test instance of specified package_key mounted under
+        specified name. Will create it if it is not found. It is
+        currently assumed the instance will be mounted under the main
+        subsite.
+
+        @param package_key package to be instantiated
+        @param instance name name of the site-node this instance will
+               be mounted to. Will default to <package_key>-test
+        @param empty require an empty instance. If an existing
+               instance is found, it will be deleted. If a package
+               different than <package_key> is found, it won't be
+               deleted and the proc will return an error
+
+        @return a package_id
+    } {
+        set main_node_id [site_node::get_element \
+                              -url / -element node_id]
+
+        set instance_name [expr {$instance_name eq "" ?
+                                 "${package_key}-test" : [string trim $instance_name /]}]
+
+        set package_exists_p [::xo::dc 0or1row lookup_test_package {
+            select node_id, object_id as package_id
+            from site_nodes
+            where parent_id = :main_node_id
+            and name = :instance_name
+        }]
+
+        if {$package_exists_p} {
+            set existing_package_key [apm_package_key_from_id $package_id]
+            if {$existing_package_key ne $package_key} {
+                error "An instance of '$existing_package_key' is already mounted at '$instance_name'"
+            } elseif {$empty_p} {
+                site_node::delete -node_id $node_id -delete_package
+            }
+        }
+
+        if {!$package_exists_p || $empty_p} {
+            set package_id [site_node::instantiate_and_mount \
+                                -package_name $instance_name \
+                                -node_name $instance_name \
+                                -package_key $package_key]
+        }
+
+        return $package_id
+    }
+
     ad_proc -public ::acs::test::form_reply {
         {-user_id 0}
         {-last_request ""}