handle the number 0 in build_list and insert_list

fixes #231

lib/ex_machina.ex

@@ -46,8 +46,8 @@ defmodule ExMachina do
         ExMachina.build_pair(__MODULE__, factory_name, attrs)
       end
 
-      def build_list(number_of_factories, factory_name, attrs \\ %{}) do
-        ExMachina.build_list(__MODULE__, number_of_factories, factory_name, attrs)
+      def build_list(number_of_records, factory_name, attrs \\ %{}) do
+        ExMachina.build_list(__MODULE__, number_of_records, factory_name, attrs)
       end
 
       @spec create(any) :: no_return
@@ -179,10 +179,11 @@ defmodule ExMachina do
       # Returns a list of 3 users
       build_list(3, :user)
   """
-  def build_list(module, number_of_factories, factory_name, attrs \\ %{}) do
-    Enum.map 1..number_of_factories, fn(_) ->
+  def build_list(module, number_of_records, factory_name, attrs \\ %{}) do
+    Stream.repeatedly(fn ->
       ExMachina.build(module, factory_name, attrs)
-    end
+    end)
+    |> Enum.take(number_of_records)
   end
 
   defmacro __before_compile__(_env) do

lib/ex_machina/strategy.ex

@@ -75,9 +75,10 @@ defmodule ExMachina.Strategy do
           end
 
           def unquote(:"#{function_name}_list")(number_of_records, factory_name, attrs \\ %{}) do
-            Enum.map 1..number_of_records, fn(_) ->
+            Stream.repeatedly(fn ->
               unquote(function_name)(factory_name, attrs)
-            end
+            end)
+            |> Enum.take(number_of_records)
           end
         end
       end

test/ex_machina/ecto_test.exs

@@ -30,6 +30,10 @@ defmodule ExMachina.EctoTest do
     assert [%User{}, %User{}, %User{}] = TestFactory.insert_list(3, :user, admin: true)
   end
 
+  test "insert_list/3 handles the number 0" do
+    assert [] = TestFactory.insert_list(0, :user)
+  end
+
   test "params_for/2 removes Ecto specific fields" do
     assert TestFactory.params_for(:user) == %{
       name: "John Doe",

test/ex_machina_test.exs

@@ -99,6 +99,10 @@ defmodule ExMachinaTest do
     assert records == [expected_record, expected_record, expected_record]
   end
 
+  test "build_list/3 handles the number 0" do
+    assert [] = Factory.build_list(0, :user)
+  end
+
   test "raises helpful error when using old create functions" do
     assert_raise RuntimeError, ~r/create\/1 has been removed/, fn ->
       Factory.create(:user)