diff --git a/lib/iris/tests/test_basic_maths.py b/lib/iris/tests/test_basic_maths.py
index c4d7b51a06..14df396915 100644
--- a/lib/iris/tests/test_basic_maths.py
+++ b/lib/iris/tests/test_basic_maths.py
@@ -554,7 +554,7 @@ def test_square_root(self):
 
         e = a ** 0.5
 
-        self.assertArrayEqual(e.data, a.data ** 0.5)
+        self.assertArrayAllClose(e.data, a.data ** 0.5)
         self.assertCML(e, ("analysis", "sqrt.cml"))
         self.assertRaises(ValueError, iris.analysis.maths.exponentiate, a, 0.3)