DEV: Add rspec tests for `SignalTrapLogger` (#27302)

Follow-up to 23c38cbf11

lib/signal_trap_logger_spec.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+RSpec.describe SignalTrapLogger do
+  describe "#log" do
+    it "should queue up messages to be logged which will then be logged by the logging thread" do
+      fake_logger = FakeLogger.new
+
+      SignalTrapLogger.instance.log(fake_logger, "message 1", level: :error)
+
+      # Ensures that thread doesn't die even if an error is encountered
+      SignalTrapLogger.instance.log(fake_logger, "error", level: :abcdes)
+
+      SignalTrapLogger.instance.log(fake_logger, "message 2", level: :info)
+
+      wait_for { fake_logger.errors.size == 1 && fake_logger.infos.size == 1 }
+
+      expect(fake_logger.errors).to eq(["message 1"])
+      expect(fake_logger.infos).to eq(["message 2"])
+    end
+  end
+end