diff --git a/test/digit_calculator_test.exs b/test/digit_calculator_test.exs
new file mode 100644
index 0000000..d3678dc
--- /dev/null
+++ b/test/digit_calculator_test.exs
@@ -0,0 +1,31 @@
+defmodule BRAN.DigitCalculatorTest do
+  use ExUnit.Case
+  use ExUnit.Parameterized
+
+  alias BRAN.DigitCalculatorTest
+
+  @itau_weight [2, 1, 2, 1, 2, 1, 2, 1, 2]
+  @itau_mod_factor 10
+
+  test_with_params "returns mod to consider on Itau validation",
+                   fn account_number, mod_factor, weights, sum_result, expected ->
+                     assert DigitCalculator.mod(
+                              account_number,
+                              mod_factor,
+                              weights,
+                              sum_result
+                            ) == expected
+                   end do
+    [
+      # Valid Accounts
+      {[4, 3, 1, 3, 4, 3, 1, 2, 9, 0], @itau_mod_factor, @itau_weight, true, 10},
+      {
+        [7, 0, 6, 8, 6, 0, 5, 2, 8, 8],
+        @itau_mod_factor,
+        @itau_weight,
+        true,
+        1
+      }
+    ]
+  end
+end