diff --git a/tests/pdegen/ppde2d.f90 b/tests/pdegen/ppde2d.f90
index 4b94f811..1d4a549b 100644
--- a/tests/pdegen/ppde2d.f90
+++ b/tests/pdegen/ppde2d.f90
@@ -99,7 +99,7 @@ contains
     a2=1.d0/80
   end function a2
   function g(x,y)
-    use psb_base_mod, only : psb_dpk_, done
+    use psb_base_mod, only : psb_dpk_, done, dzero
     real(psb_dpk_) ::  g
     real(psb_dpk_), intent(in) :: x,y
     g = dzero
diff --git a/tests/pdegen/ppde3d.f90 b/tests/pdegen/ppde3d.f90
index 6c638b2d..1247deb6 100644
--- a/tests/pdegen/ppde3d.f90
+++ b/tests/pdegen/ppde3d.f90
@@ -111,7 +111,7 @@ contains
     a3=1.d0/80
   end function a3
   function g(x,y,z)
-    use psb_base_mod, only : psb_dpk_, done
+    use psb_base_mod, only : psb_dpk_, done, dzero
     real(psb_dpk_) ::  g
     real(psb_dpk_), intent(in) :: x,y,z
     g = dzero
diff --git a/tests/pdegen/spde2d.f90 b/tests/pdegen/spde2d.f90
index 9155978d..b0d47499 100644
--- a/tests/pdegen/spde2d.f90
+++ b/tests/pdegen/spde2d.f90
@@ -99,7 +99,7 @@ contains
     a2=1.e0/80
   end function a2
   function g(x,y)
-    use psb_base_mod, only : psb_spk_, sone
+    use psb_base_mod, only : psb_spk_, sone, szero
     real(psb_spk_) ::  g
     real(psb_spk_), intent(in) :: x,y
     g = szero
diff --git a/tests/pdegen/spde3d.f90 b/tests/pdegen/spde3d.f90
index 8ca1f0ba..2cfd7d0f 100644
--- a/tests/pdegen/spde3d.f90
+++ b/tests/pdegen/spde3d.f90
@@ -111,7 +111,7 @@ contains
     a3=1.e0/80
   end function a3
   function g(x,y,z)
-    use psb_base_mod, only : psb_spk_, sone
+    use psb_base_mod, only : psb_spk_, sone, szero
     real(psb_spk_) ::  g
     real(psb_spk_), intent(in) :: x,y,z
     g = szero