diff --git a/test/matrix/test_matrix.rb b/test/matrix/test_matrix.rb
index 7c466e6..bef03fa 100644
--- a/test/matrix/test_matrix.rb
+++ b/test/matrix/test_matrix.rb
@@ -274,6 +274,34 @@ class TestMatrix < Test::Unit::TestCase
     assert_raise(ExceptionForMatrix::ErrDimensionMismatch) { Matrix[[2,0,1],[0,-2,2]].cofactor(0, 0) }
   end
 
+  def test_column_merge
+    assert_equal(Matrix.empty(4, 0), Matrix.empty(2, 0).column_merge(Matrix.empty(2, 0)))
+    assert_equal(Matrix[[1], [2], [3]], Matrix[[1]].column_merge(Matrix[[2], [3]]))
+
+    assert_equal(
+      Matrix[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]],
+      Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5, 6], [7, 8], [9, 10]])
+    )
+
+    assert_equal(
+      Matrix[[1, 2], [3, 4], [5, 6]],
+      Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5, 6]])
+    )
+
+    assert_equal(
+      Matrix[[1, 2], [3, 4], [5, 6], [7, 8]],
+      Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5, 6]], Matrix[[7, 8]])
+    )
+
+    assert_raise(ExceptionForMatrix::ErrDimensionMismatch) do
+      Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5, 6, 7], [8, 9, 10]])
+    end
+
+    assert_raise(ExceptionForMatrix::ErrDimensionMismatch) do
+      Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5], [6]])
+    end
+  end
+
   def test_regular?
     assert(Matrix[[1, 0], [0, 1]].regular?)
     assert(Matrix[[1, 0, 0], [0, 1, 0], [0, 0, 1]].regular?)