From 64ae82bef0e1c2e9de3532b0136368c5772fe05f Mon Sep 17 00:00:00 2001
From: Moises Macia <mmacia@gmail.com>
Date: Mon, 30 Mar 2026 20:21:25 +0000
Subject: [PATCH] add tests

---
 test/feed_reader/xml_resource_limits_test.exs | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 test/feed_reader/xml_resource_limits_test.exs

diff --git a/test/feed_reader/xml_resource_limits_test.exs b/test/feed_reader/xml_resource_limits_test.exs
new file mode 100644
index 0000000..31b0222
--- /dev/null
+++ b/test/feed_reader/xml_resource_limits_test.exs
@@ -0,0 +1,86 @@
+defmodule FeedReader.XMLResourceLimitsTest do
+  use ExUnit.Case, async: true
+
+  alias FeedReader.XMLResourceLimits
+
+  test "uses finite defaults and falls back for invalid limits" do
+    defaults = XMLResourceLimits.new()
+
+    assert defaults.max_xml_events == 1_000_000
+    assert defaults.max_xml_depth == 256
+    assert defaults.max_attributes_per_element == 128
+    assert defaults.max_attribute_bytes == 65_536
+    assert defaults.max_feed_metadata_bytes == 1_048_576
+    assert defaults.max_item_bytes == 4_194_304
+
+    limits = XMLResourceLimits.new(max_xml_events: -1, max_item_bytes: :unbounded)
+    assert limits.max_xml_events == defaults.max_xml_events
+    assert limits.max_item_bytes == defaults.max_item_bytes
+  end
+
+  test "rejects unsupported events and malformed SAX payloads" do
+    limits = XMLResourceLimits.new()
+
+    assert {:error, :invalid_sax_event} =
+             XMLResourceLimits.account_event(limits, :processing_instruction, "data")
+
+    assert {:error, :invalid_sax_event} =
+             XMLResourceLimits.account_event(limits, :start_element, {"root", [{"attr", 1}]})
+
+    assert {:error, :invalid_sax_event} =
+             XMLResourceLimits.account_event(limits, :end_element, "root")
+  end
+
+  test "counts SAX events and rejects depth before accepting another element" do
+    limits = XMLResourceLimits.new(max_xml_events: 3, max_xml_depth: 1)
+    assert {:ok, limits} = XMLResourceLimits.account_event(limits, :start_document, [])
+    assert {:ok, limits} = XMLResourceLimits.account_event(limits, :start_element, {"root", []})
+
+    assert {:error, {:resource_limit, :max_xml_depth, 1}} =
+             XMLResourceLimits.account_event(limits, :start_element, {"nested", []})
+
+    assert {:ok, limits} = XMLResourceLimits.account_event(limits, :end_element, "root")
+
+    assert {:error, {:resource_limit, :max_xml_events, 3}} =
+             XMLResourceLimits.account_event(limits, :end_document, [])
+  end
+
+  test "bounds per-element attribute count and attribute byte length" do
+    limits = XMLResourceLimits.new(max_attributes_per_element: 1, max_attribute_bytes: 5)
+
+    assert {:error, {:resource_limit, :max_attributes_per_element, 1}} =
+             XMLResourceLimits.account_event(
+               limits,
+               :start_element,
+               {"x", [{"a", "1"}, {"b", "2"}]}
+             )
+
+    limits = XMLResourceLimits.new(max_attribute_bytes: 5)
+
+    assert {:error, {:resource_limit, :max_attribute_bytes, 5}} =
+             XMLResourceLimits.account_event(limits, :start_element, {"x", [{"a", "12345"}]})
+  end
+
+  test "charges SAX text and attributes to the active metadata or item budget" do
+    limits = XMLResourceLimits.new(max_feed_metadata_bytes: 4, max_item_bytes: 5)
+    limits = XMLResourceLimits.set_scope(limits, :feed)
+
+    assert {:error, {:resource_limit, :max_feed_metadata_bytes, 4}} =
+             XMLResourceLimits.account_event(limits, :start_element, {"x", [{"a", "123"}]})
+
+    assert {:ok, limits} = XMLResourceLimits.account_event(limits, :characters, "feed")
+
+    assert {:error, {:resource_limit, :max_feed_metadata_bytes, 4}} =
+             XMLResourceLimits.account_event(limits, :characters, "!")
+
+    limits = XMLResourceLimits.set_scope(limits, :item)
+    assert {:ok, limits} = XMLResourceLimits.account_event(limits, :start_element, {"x", []})
+    assert {:ok, limits} = XMLResourceLimits.account_event(limits, :cdata, "item")
+
+    assert {:error, {:resource_limit, :max_item_bytes, 5}} =
+             XMLResourceLimits.account_event(limits, :characters, "!")
+
+    limits = XMLResourceLimits.set_scope(limits, :item)
+    assert {:ok, _limits} = XMLResourceLimits.account_event(limits, :characters, "fresh")
+  end
+end