Support lists as sample data root arguments

We documented that we support lists as sample data root values, but in
practice we did not.

This fix allows for setting lists as custom sample data (and other types
of sample data) as shown in the changeset.

.changesets/support-lists-as-root-sample-data.md

@@ -0,0 +1,17 @@
+---
+bump: "patch"
+type: "change"
+---
+
+Add support for lists in the sample data as root values on spans, as shown below. Previously we only supported lists as nested objects in maps.
+
+```elixir
+Appsignal.Span.set_sample_data(
+  Appsignal.Tracer.root_span,
+  "custom_data",
+  [
+    "value 1",
+    "value 2"
+  ]
+)
+```

lib/appsignal/span.ex

@@ -242,7 +242,7 @@ defmodule Appsignal.Span do
   end
 
   defp do_set_sample_data(%Span{reference: reference} = span, key, value, setter)
-       when is_binary(key) and is_map(value) do
+       when is_binary(key) and (is_map(value) or is_list(value)) do
     data = Appsignal.Utils.DataEncoder.encode(value)
 
     :ok = setter.(reference, key, data)

test/appsignal/span_test.exs

@@ -504,6 +504,36 @@ defmodule AppsignalSpanTest do
     end
   end
 
+  describe ".set_sample_data/3, with a list" do
+    setup :create_root_span
+
+    setup %{span: span} do
+      Span.set_sample_data(span, "custom_data", ["abc", "def"])
+
+      :ok
+    end
+
+    @tag :skip_env_test_no_nif
+    test "sets the list as sample data", %{span: span} do
+      assert %{"sample_data" => %{"custom_data" => "[\"abc\",\"def\"]"}} = Span.to_map(span)
+    end
+  end
+
+  describe ".set_sample_data/3, with a keyword list" do
+    setup :create_root_span
+
+    setup %{span: span} do
+      Span.set_sample_data(span, "custom_data", abc: "def")
+
+      :ok
+    end
+
+    @tag :skip_env_test_no_nif
+    test "sets the keyword list as sample data", %{span: span} do
+      assert %{"sample_data" => %{"custom_data" => "[[\"abc\",\"def\"]]"}} = Span.to_map(span)
+    end
+  end
+
   describe ".set_sample_data/3, when passing invalid data" do
     setup :create_root_span
 
@@ -655,6 +685,36 @@ defmodule AppsignalSpanTest do
     end
   end
 
+  describe ".set_sample_data_if_nil/3, with a list" do
+    setup :create_root_span
+
+    setup %{span: span} do
+      Span.set_sample_data_if_nil(span, "custom_data", ["abc", "def"])
+
+      :ok
+    end
+
+    @tag :skip_env_test_no_nif
+    test "sets the list as sample data", %{span: span} do
+      assert %{"sample_data" => %{"custom_data" => "[\"abc\",\"def\"]"}} = Span.to_map(span)
+    end
+  end
+
+  describe ".set_sample_data_if_nil/3, with a keyword list" do
+    setup :create_root_span
+
+    setup %{span: span} do
+      Span.set_sample_data_if_nil(span, "custom_data", abc: "def")
+
+      :ok
+    end
+
+    @tag :skip_env_test_no_nif
+    test "sets the keyword list as sample data", %{span: span} do
+      assert %{"sample_data" => %{"custom_data" => "[[\"abc\",\"def\"]]"}} = Span.to_map(span)
+    end
+  end
+
   describe ".set_sample_data_if_nil/3, when passing invalid data" do
     setup :create_root_span