Unit test

app/lib/audit_log_formatter.rb

@@ -4,7 +4,7 @@ def call(severity, timestamp, _progname, message)
     request_id = Thread.current[:request_id]
     json = {
       type: severity,
-      time: timestamp,
+      time: "#{timestamp}",
       request_id: request_id
     }
     if message.is_a? Hash

test/lib/audit_log_formatter_test.rb

@@ -0,0 +1,24 @@
+require "test_helper"
+
+class AuditLogFormatterTest < ActiveSupport::TestCase
+  test "#call formats logformatter inputs as json" do
+    t = Time.now
+    result = AuditLogFormatter.new.call("info", t, nil, "some message")
+    assert_equal %Q({"type":"info","time":"#{t}","request_id":null,"message":"some message"}\n), result
+  end
+
+  test "#call accepts and merges a Hash type for the message" do
+    t = Time.now
+    result = AuditLogFormatter.new.call("info", t, nil, { key: "some message", key2: "another" })
+    assert_equal %Q({"type":"info","time":"#{t}","request_id":null,"key":"some message","key2":"another"}\n), result
+  end
+
+  test "#call can render a thread local request_id" do
+    t = Time.now
+    req_id = SecureRandom.hex
+    Thread.stub :current, { request_id: req_id } do
+      result = AuditLogFormatter.new.call("info", t, nil, { key: "some message" })
+      assert_equal %Q({"type":"info","time":"#{t}","request_id":"#{req_id}","key":"some message"}\n), result
+    end
+  end
+end