diff --git a/lib/galaxy/tools/parameters/basic.py b/lib/galaxy/tools/parameters/basic.py
index bf966644e47..690bf4039b1 100644
--- a/lib/galaxy/tools/parameters/basic.py
+++ b/lib/galaxy/tools/parameters/basic.py
@@ -1739,7 +1739,13 @@ class DataToolParameter( ToolParameter ):
         if isinstance( value, str ) and value.find( "," ) > 0:
             value = [ int( value_part ) for value_part in  value.split( "," ) ]
         if isinstance( value, list ):
-            rval = [ trans.sa_session.query( trans.app.model.HistoryDatasetAssociation ).get( v ) for v in value ]
+            rval = []
+            for single_value in value:
+                if isinstance( single_value, dict ):
+                    assert single_value['src'] == 'hda'
+                    rval.append( trans.sa_session.query( trans.app.model.HistoryDatasetAssociation ).get( trans.app.security.decode_id( single_value[ 'id' ] ) ) )
+                else:
+                    rval.append( trans.sa_session.query( trans.app.model.HistoryDatasetAssociation ).get( single_value ) )
         elif isinstance( value, trans.app.model.HistoryDatasetAssociation ):
             rval = value
         elif isinstance( value, dict ) and 'src' in value and 'id' in value:
diff --git a/lib/galaxy/tools/test.py b/lib/galaxy/tools/test.py
index 73939003932..0c6eb3379f3 100644
--- a/lib/galaxy/tools/test.py
+++ b/lib/galaxy/tools/test.py
@@ -179,10 +179,12 @@ class ToolTestBuilder( object ):
                 raw_input = context.extract_value( raw_inputs )
                 if raw_input:
                     (name, param_value, param_extra) = raw_input
+                    param_value = self.__split_if_str( param_value )
                     if isinstance( value, basic.DataToolParameter ):
-                        processed_value = [ self.__add_uploaded_dataset( context.for_state(), param_value, param_extra, value ) ]
+                        if not isinstance(param_value, list):
+                            param_value = [ param_value ]
+                        processed_value = [ self.__add_uploaded_dataset( context.for_state(), v, param_extra, value ) for v in param_value ]
                     else:
-                        param_value = self.__split_if_str( param_value )
                         processed_value = param_value
                     expanded_inputs[ context.for_state() ] = processed_value
         return expanded_inputs
@@ -309,7 +311,7 @@ def __parse_output_elem( output_elem ):
     for metadata_elem in output_elem.findall( 'metadata' ):
         metadata[ metadata_elem.get('name') ] = metadata_elem.get( 'value' )
     if not (assert_list or file or extra_files or metadata):
-        raise Exception( "Test output defines not checks (e.g. must have a 'file' check against, assertions to check, etc...)")
+        raise Exception( "Test output defines nothting to check (e.g. must have a 'file' check against, assertions to check, etc...)")
     attributes['assert_list'] = assert_list
     attributes['extra_files'] = extra_files
     attributes['metadata'] = metadata
diff --git a/test/base/interactor.py b/test/base/interactor.py
index c67ef365943..f19be62c443 100644
--- a/test/base/interactor.py
+++ b/test/base/interactor.py
@@ -133,9 +133,13 @@ class GalaxyInteractorApi( object ):
         inputs_tree = testdef.inputs.copy()
         for key, value in inputs_tree.iteritems():
             values = [value] if not isinstance(value, list) else value
+            new_values = []
             for value in values:
                 if value in self.uploads:
-                    inputs_tree[ key ] = self.uploads[ value ]
+                    new_values.append( self.uploads[ value ] )
+                else:
+                    new_values.append( value )
+            inputs_tree[ key ] = new_values
 
         # # HACK: Flatten single-value lists. Required when using expand_grouping
         for key, value in inputs_tree.iteritems():
diff --git a/test/functional/tools/multi_data_param.xml b/test/functional/tools/multi_data_param.xml
index 57f94b29c10..9ffe8bbabe3 100644
--- a/test/functional/tools/multi_data_param.xml
+++ b/test/functional/tools/multi_data_param.xml
@@ -18,13 +18,23 @@
       <output name="out1" file="simple_line.txt" />
       <output name="out2" file="simple_line_alternative.txt" />
     </test>
-    <!-- TODO: Support this or something like this.
+    <test>
+      <param name="f1" value="simple_line.txt,simple_line_alternative.txt" />
+      <param name="f2" value="simple_line_alternative.txt" />
+      <output name="out1">
+        <assert_contents>
+          <has_line line="This is a line of text." />
+          <has_line line="This is a different line of text." />
+        </assert_contents>
+      </output>
+    </test>
+    <!-- Twill interactor cannot do these latter two, but not even 
+         UI widget can do this next one. -->
     <test>
       <param name="f1" value="simple_line.txt,simple_line.txt" />
       <param name="f2" value="simple_line_alternative.txt" />
       <output name="out1" file="simple_line_x2.txt" />
-      <output name="out1" file="simple_line_alternative.txt" />
+      <output name="out2" file="simple_line_alternative.txt" />
     </test>
-    -->
   </tests>
 </tool>