adding gun adapter

test/otp_version_test.exs

@@ -0,0 +1,58 @@
+defmodule Pleroma.OTPVersionTest do
+  use ExUnit.Case, async: true
+
+  alias Pleroma.OTPVersion
+
+  describe "get_and_check_version/2" do
+    test "22.4" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/22.4"
+             ]) == :ok
+    end
+
+    test "22.1" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/22.1"
+             ]) == {:error, "22.1"}
+    end
+
+    test "21.1" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/21.1"
+             ]) == {:error, "21.1"}
+    end
+
+    test "23.0" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/23.0"
+             ]) == :ok
+    end
+
+    test "undefined" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/undefined"
+             ]) == :undefined
+    end
+
+    test "not parsable" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/error"
+             ]) == :undefined
+    end
+
+    test "with non existance file" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, [
+               "test/fixtures/warnings/otp_version/non-exising",
+               "test/fixtures/warnings/otp_version/22.4"
+             ]) == :ok
+    end
+
+    test "empty paths" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Gun, []) == :undefined
+    end
+
+    test "another adapter" do
+      assert OTPVersion.get_and_check_version(Tesla.Adapter.Hackney, []) == :ok
+    end
+  end
+end