clear memoized x509 cert on Cert#cert_pem assignment

lib/puma/acme/structs.rb

@@ -59,6 +59,12 @@ def initialize(identifiers: nil, **kwargs)
         super(identifiers: identifiers, **kwargs)
       end
 
+      def cert_pem=(pem)
+        @x509 = nil
+
+        self[:cert_pem] = pem
+      end
+
       def key
         [:cert, algorithm, identifiers&.map(&:key)]
       end

puma-acme.gemspec

@@ -29,6 +29,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'http.rb', '~> 0.12'
   s.add_development_dependency 'minitest', '~> 5.14'
   s.add_development_dependency 'minitest-mock_expectations', '~> 1.2'
+  s.add_development_dependency 'r509', '~> 1.0'
   s.add_development_dependency 'rake', '~> 13.0'
   s.add_development_dependency 'vcr', '~> 6.1'
   s.add_development_dependency 'webmock', '~> 3.19'

test/structs_test.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require_relative './test_helper'
+
+class CertsTest < Minitest::Test
+  def test_changing_pem_changes_cert_properties
+    key = R509::PrivateKey.new(type: 'RSA', bit_length: 2048)
+    expired_at = Time.now.utc.to_i - 3600
+    expired_pem = cert_pem(key, 'expired.test', not_before: expired_at - 3600, not_after: expired_at)
+
+    cert = Puma::Acme::Cert.new(algorithm: :rsa, identifiers: %w[expired.test], cert_pem: expired_pem)
+    assert cert.expired?
+
+
+    unexpired_at = Time.now.utc.to_i
+    unexpired_pem = cert_pem(key, 'unexpired.test', not_before: unexpired_at - 3600, not_after: unexpired_at + 3600)
+
+    cert.cert_pem = unexpired_pem
+    assert !cert.expired?
+  end
+
+  protected
+
+  def cert_pem(key, common_name, not_before:, not_after:)
+    csr = R509::CSR.new(
+      subject: [['CN', common_name]],
+      message_digest: 'SHA256',
+      key: key
+    )
+
+    cert = R509::CertificateAuthority::Signer.selfsign(
+      csr: csr,
+      not_before: not_before,
+      not_after: not_after
+    )
+
+    cert.to_pem
+  end
+end

test/test_helper.rb

@@ -11,6 +11,7 @@
 require 'minitest/mock_expectations'
 require 'puma/configuration'
 require 'puma/events'
+require 'r509'
 require 'securerandom'
 require 'vcr'
 require 'webmock'