diff --git a/tests/affine2.rs b/tests/affine2.rs
index 08cbd3bd..205caa40 100644
--- a/tests/affine2.rs
+++ b/tests/affine2.rs
@@ -220,6 +220,10 @@ macro_rules! impl_affine2_tests {
             assert_approx_eq!(m0, m0 * $affine2::IDENTITY);
             assert_approx_eq!(m0, $affine2::IDENTITY * m0);
 
+            let mut m1 = m0;
+            m1 *= $affine2::IDENTITY;
+            assert_approx_eq!(m1, m0);
+
             let mat3 = $mat3::from(m0);
             assert_approx_eq!(mat3, $affine2::IDENTITY * mat3);
             assert_approx_eq!(mat3, mat3 * $affine2::IDENTITY);
diff --git a/tests/affine3.rs b/tests/affine3.rs
index a711da1b..49c43916 100644
--- a/tests/affine3.rs
+++ b/tests/affine3.rs
@@ -294,6 +294,10 @@ macro_rules! impl_affine3_tests {
             assert_approx_eq!(m0, m0 * $affine3::IDENTITY);
             assert_approx_eq!(m0, $affine3::IDENTITY * m0);
 
+            let mut m1 = m0;
+            m1 *= $affine3::IDENTITY;
+            assert_approx_eq!(m1, m0);
+
             let mat4 = $mat4::from(m0);
             assert_approx_eq!(mat4, $affine3::IDENTITY * mat4);
             assert_approx_eq!(mat4, mat4 * $affine3::IDENTITY);