add global tan function
diff --git a/test/array.cpp b/test/array.cpp
index 7da4c99..26c6c33 100644
--- a/test/array.cpp
+++ b/test/array.cpp
@@ -173,6 +173,8 @@
   VERIFY_IS_APPROX(m1.sin(), internal::sin(m1));
   VERIFY_IS_APPROX(m1.cos(), std::cos(m1));
   VERIFY_IS_APPROX(m1.cos(), internal::cos(m1));
+  VERIFY_IS_APPROX(m1.tan(), std::tan(m1));
+  VERIFY_IS_APPROX(m1.tan(), internal::tan(m1));
 
   VERIFY_IS_APPROX(internal::cos(m1+RealScalar(3)*m2), internal::cos((m1+RealScalar(3)*m2).eval()));
   VERIFY_IS_APPROX(std::cos(m1+RealScalar(3)*m2), std::cos((m1+RealScalar(3)*m2).eval()));