diff --git a/src/xSTIR/pSTIR/tests/tests_two.py b/src/xSTIR/pSTIR/tests/tests_two.py
index a800bade1..433cbf01e 100644
--- a/src/xSTIR/pSTIR/tests/tests_two.py
+++ b/src/xSTIR/pSTIR/tests/tests_two.py
@@ -36,7 +36,7 @@ def test_main(rec=False, verb=False, throw=True):
         test.check(acq_data.norm())
 
         image = acq_data.create_uniform_image(1.0)
-        test.check(image.norm())
+        test.check_if_equal_within_tolerance(image.norm(), numpy.sqrt(numpy.prod(image.dimensions())))
 
         acq_model = AcquisitionModelUsingRayTracingMatrix()
         acq_model.set_up(acq_data, image)
diff --git a/src/xSTIR/pSTIR/tests/tests_two.txt b/src/xSTIR/pSTIR/tests/tests_two.txt
index 741a81428..47425693b 100644
--- a/src/xSTIR/pSTIR/tests/tests_two.txt
+++ b/src/xSTIR/pSTIR/tests/tests_two.txt
@@ -1,6 +1,4 @@
 4.932500e+04
-7.182416e+02
 2.256327e+02
 4.932500e+04
-7.182416e+02
 2.256327e+02