Raise in Time.add/3 for non-positive integer (#13122)

Author: 03juan

lib/elixir/lib/calendar/time.ex

@@ -515,10 +515,11 @@ defmodule Time do
 
   def add(%{calendar: calendar, microsecond: {_, precision}} = time, amount_to_add, unit)
       when is_integer(amount_to_add) do
-    if not is_integer(unit) and
+    if (is_integer(unit) and unit < 1) or
          unit not in ~w(second millisecond microsecond nanosecond)a do
       raise ArgumentError,
-            "unsupported time unit. Expected :hour, :minute, :second, :millisecond, :microsecond, :nanosecond, or a positive integer, got #{inspect(unit)}"
+            "unsupported time unit. Expected :hour, :minute, :second, :millisecond, " <>
+              ":microsecond, :nanosecond, or a positive integer, got #{inspect(unit)}"
     end
 
     amount_to_add = System.convert_time_unit(amount_to_add, unit, :microsecond)

lib/elixir/test/elixir/calendar/time_test.exs

@@ -90,4 +90,14 @@ defmodule TimeTest do
 
     assert Time.truncate(~T[01:01:01.123456], :second) == ~T[01:01:01]
   end
+
+  test "add/3" do
+    time = ~T[00:00:00.0]
+
+    assert Time.add(time, 1, :hour) == ~T[01:00:00.0]
+
+    assert_raise ArgumentError, ~r/Expected :hour, :minute, :second/, fn ->
+      Time.add(time, 1, 0)
+    end
+  end
 end