diff --git a/tools/rptools/rpfba.xml b/tools/rptools/rpfba.xml
index 4e7a78de..cf37f964 100644
--- a/tools/rptools/rpfba.xml
+++ b/tools/rptools/rpfba.xml
@@ -65,7 +65,7 @@
         </data>
     </outputs>
     <tests>
-        <test>
+        <test expect_num_outputs="1">
         <!-- test 1: check if identical outputs are produced with R_BIOMASS__3 biomass name ID and BiGG model (iCN718)  -->
             <param name="pathway" value="rp_001_0001_rpfba_in.xml" />
             <param name="model" value="iCN718.xml.gz" />
@@ -81,7 +81,7 @@
                 </assert_contents>
             </output>
         </test>
-        <test>
+        <test expect_num_outputs="1">
         <!-- test 2: check if identical outputs are produced with R_BIOMASS__3 biomass name ID and BiGG model (iCN718)  and sim_type=fba-->
             <param name="pathway" value="rp_001_0001_rpfba_in.xml" />
             <param name="model" value="iCN718.xml.gz" />
@@ -99,7 +99,7 @@
                 </assert_contents>
             </output>
         </test>
-        <test>
+        <test expect_num_outputs="1">
         <!-- test 3: check if identical outputs are produced with R_DM_biomass_c biomass name ID and BiGG model (iCN718)  and sim_type=pfba-->
             <param name="pathway" value="rp_001_0001_rpfba_in.xml" />
             <param name="model" value="iCN718.xml.gz" />