fix nil case (#33)

lib/ex_parameterized/params.ex

@@ -49,12 +49,14 @@ defmodule ExUnit.Parameterized.Params do
     end)
   end
 
-  defp test_with(desc, fun, {{param_desc, {_, _, values}}, num}) when is_atom(param_desc) do
+  defp test_with(desc, fun, {{param_desc, {_, _, values}}, num})
+       when is_atom(param_desc) and not is_nil(param_desc) do
     run("'#{desc}': '#{param_desc}': number of #{num}", fun, values)
   end
 
   # Quote literals case : http://elixir-lang.org/docs/master/elixir/Kernel.SpecialForms.html#quote/2
-  defp test_with(desc, fun, {{param_desc, values}, num}) when is_atom(param_desc) do
+  defp test_with(desc, fun, {{param_desc, values}, num})
+       when is_atom(param_desc) and not is_nil(param_desc) do
     run("'#{desc}': '#{param_desc}': number of #{num}", fun, escape_values(values))
   end
 

lib/ex_parameterized/params_callback.ex

@@ -52,12 +52,14 @@ defmodule ExUnit.Parameterized.ParamsCallback do
     end)
   end
 
-  defp test_with(desc, context, fun, {{param_desc, {_, _, values}}, num}) when is_atom(param_desc) do
+  defp test_with(desc, context, fun, {{param_desc, {_, _, values}}, num})
+       when is_atom(param_desc) and not is_nil(param_desc) do
     run("'#{desc}': '#{param_desc}': number of #{num}", context, fun, values)
   end
 
   # Quote literals case : http://elixir-lang.org/docs/master/elixir/Kernel.SpecialForms.html#quote/2
-  defp test_with(desc, context, fun, {{param_desc, values}, num}) when is_atom(param_desc) do
+  defp test_with(desc, context, fun, {{param_desc, values}, num})
+       when is_atom(param_desc) and not is_nil(param_desc) do
     run("'#{desc}': '#{param_desc}': number of #{num}", context, fun, escape_values(values))
   end
 

test/ex_parameterized_callback_test.exs

@@ -3,7 +3,7 @@ defmodule ExParameterizedParamsCallbackTest do
   use ExUnit.Parameterized
 
   setup do
-    {:ok, [hello: "world", value: 1, bool: false]}
+    {:ok, [hello: "world", value: 1, bool: false, nil_value: nil]}
   end
 
   test "ast format when one param with context" do
@@ -96,6 +96,16 @@ defmodule ExParameterizedParamsCallbackTest do
     ]
   end
 
+  test_with_params "with nil", context, fn expected, a, b ->
+    assert a == expected
+    assert b == expected
+  end do
+    [
+      {context[:value], 1, 1},
+      {context[:nil_value], nil, nil}
+    ]
+  end
+
   test_with_params "with map value", context, fn a ->
     assert a.b == 1
     assert a.c == 2

test/ex_parameterized_test.exs

@@ -65,6 +65,15 @@ defmodule ExParameterizedTest do
     ]
   end
 
+  test_with_params "with nil", fn a, b ->
+    assert a == b
+  end do
+    [
+      {1, 1},
+      {nil, nil}
+    ]
+  end
+
   test_with_params "with map value", fn a ->
     assert a.b == 1
     assert a.c == 2