diff --git a/compareECLFiles.cmake b/compareECLFiles.cmake
index 1a44e9474..a303f3f91 100755
--- a/compareECLFiles.cmake
+++ b/compareECLFiles.cmake
@@ -464,6 +464,13 @@ add_test_compareECLFiles(CASENAME pinch_multz_all_barrier
                          REL_TOL ${rel_tol}
                          DIR pinch)
 
+add_test_compareECLFiles(CASENAME udq_uadd
+                         FILENAME UDQ_M1
+                         SIMULATOR flow
+                         ABS_TOL ${abs_tol}
+                         REL_TOL ${rel_tol}
+                         DIR udq_actionx)
+
 if (opm-common_EMBEDDED_PYTHON)
   add_test_compareECLFiles(CASENAME udq_pyaction
                            FILENAME PYACTION_WCONPROD
diff --git a/tests/update_reference_data.sh b/tests/update_reference_data.sh
index d94ec158b..0758b2cfa 100755
--- a/tests/update_reference_data.sh
+++ b/tests/update_reference_data.sh
@@ -126,6 +126,7 @@ tests[polymer_injectivity]="flow polymer_injectivity 2D_POLYMER_INJECTIVITY"
 tests[nnc]="flow editnnc NNC_AND_EDITNNC nnc"
 tests[udq_wconprod]="flow udq_actionx UDQ_WCONPROD udq_wconprod"
 tests[udq_actionx]="flow udq_actionx UDQ_ACTIONX udq_actionx"
+tests[udq_M1]="flow udq_actionx UDQ_M1 udq_uadd"
 tests[udq_pyaction]="flow udq_actionx PYACTION_WCONPROD udq_pyaction"
 tests[spe1_foam]="flow spe1_foam SPE1FOAM"
 tests[wsegsicd]="flow wsegsicd TEST_WSEGSICD"