fix: Allow the Util.list to handle lengths of zero

Author: lud-wj

lib/faker/util.ex

@@ -87,13 +87,17 @@ defmodule Faker.Util do
       iex> Faker.Util.list(3, &(to_string(&1)))
       ["0", "1", "2"]
   """
-  @spec list(integer, (integer -> any)) :: [any]
-  def list(n, fun) when is_function(fun, 1) do
+  @spec list(non_neg_integer, (integer -> any)) :: [any]
+  def list(0, _) do
+    []
+  end
+
+  def list(n, fun) when is_function(fun, 1) and n > 0 do
     Enum.map(0..(n - 1), &fun.(&1))
   end
 
-  @spec list(integer, (-> any)) :: [any]
-  def list(n, fun) when is_function(fun, 0) do
+  @spec list(non_neg_integer, (-> any)) :: [any]
+  def list(n, fun) when is_function(fun, 0) and n > 0 do
     Enum.map(0..(n - 1), fn _ -> fun.() end)
   end
 

test/faker/util_test.exs

@@ -51,4 +51,12 @@ defmodule Faker.UtilTest do
       assert Enum.sort(generated_value) == list
     end)
   end
+
+  test "list/2" do
+    assert [0, 1, 2] = Faker.Util.list(3, & &1)
+  end
+
+  test "emtpty list/2" do
+    assert [] = Faker.Util.list(0, fn -> raise "not called" end)
+  end
 end