ci: run tests with and without the Erlang allocator

The allocator is selected when the NIF loads, so exercise both modes in
CI via EXQLITE_DISABLE_ERLANG_ALLOCATOR. Test config reads that env var,
and the allocator test asserts the NIF matches the configured setting.

Author: warmwaffles

.github/workflows/ci.yml

@@ -80,4 +80,11 @@ jobs:
             - run: mix deps.get --only test
             - run: mix deps.compile
             - run: mix compile
-            - run: mix test
+            - name: Test with Erlang allocator
+              run: mix test
+              env:
+                  EXQLITE_DISABLE_ERLANG_ALLOCATOR: "false"
+            - name: Test without Erlang allocator
+              run: mix test
+              env:
+                  EXQLITE_DISABLE_ERLANG_ALLOCATOR: "true"

config/config.exs

@@ -0,0 +1,11 @@
+import Config
+
+if config_env() == :test do
+  disable_erlang_allocator =
+    case System.get_env("EXQLITE_DISABLE_ERLANG_ALLOCATOR") do
+      nil -> false
+      value -> String.downcase(value) in ~w(true 1)
+    end
+
+  config :exqlite, disable_erlang_allocator: disable_erlang_allocator
+end

test/exqlite/allocator_test.exs

@@ -1,8 +1,10 @@
 defmodule Exqlite.AllocatorTest do
   use ExUnit.Case
 
-  test "erlang allocator is used by default" do
-    assert Application.get_env(:exqlite, :disable_erlang_allocator) == nil
-    assert Exqlite.Sqlite3NIF.erlang_allocator_enabled()
+  test "erlang allocator respects configuration" do
+    disabled = Application.get_env(:exqlite, :disable_erlang_allocator, false)
+
+    assert is_boolean(disabled)
+    assert Exqlite.Sqlite3NIF.erlang_allocator_enabled() == not disabled
   end
 end