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Testing Legacy Configuration Integration in Postal Server

This test suite validates the LegacyConfigSource functionality in Postal’s configuration system, ensuring proper YAML configuration parsing and integration with the Konfig::Config system. The tests verify correct value retrieval across multiple configuration groups and settings.

Test Coverage Overview

The test suite provides comprehensive coverage of configuration parsing and validation across multiple configuration groups including postal, web_server, databases, logging, SMTP, DNS, and security services.

Key functionality tested includes:

Configuration value retrieval for all major system components
Database connection parameters validation
SMTP and mail delivery settings
Security service configurations (RSPAMD, ClamAV, SPAMD)

Implementation Analysis

The testing approach focuses on integration testing rather than unit testing the LegacyConfigSource directly, validating the configuration system’s practical functionality through the Konfig::Config interface.

The implementation uses RSpec’s describe/it blocks to organize tests by configuration groups, with before hooks to neutralize schema defaults for accurate testing.

Technical Details

Testing tools and setup:

RSpec as the testing framework
Rails test environment integration
YAML configuration file parsing
Konfig::Config system for configuration management
Mock objects to override schema defaults

Best Practices Demonstrated

The test suite demonstrates several testing best practices including:

Logical grouping of related tests
Isolation of test cases from default values
Comprehensive coverage of configuration parameters
Clear test descriptions and expectations
Proper setup and mocking techniques

postalserver/postal

spec/lib/postal/legacy_config_source_spec.rb

            
# frozen_string_literal: true

require "rails_helper"

module Postal

  SOURCE_CONFIG = YAML.safe_load(File.read(Rails.root.join("spec/examples/full_legacy_config_file.yml")))

  # Rather than actuall test the LegacyConfigSource directly, I have decided
  # to test this source via. the Konfig::Config system to ensure it works as
  # expected in practice rather than just in theory. Testing '#get' would be
  # fairly easy (and mostly pointless) where as testing the values we actually
  # want are correct is preferred.
  RSpec.describe LegacyConfigSource do
    before do
      # For the purposes of testing, we want to ignore any defaults provided
      # by the schema itself. Otherwise, we might see a value returned that
      # looks correct but is actually the default rather than the value from
      # config file.
      allow_any_instance_of(Konfig::SchemaAttribute).to receive(:default) do |a|
        a.array? ? [] : nil
      end
    end

    let(:source) { described_class.new(SOURCE_CONFIG) }
    subject(:config) { Konfig::Config.build(ConfigSchema, sources: [source]) }

    describe "the 'postal' group" do
      it "returns a value for postal.web_hostname" do
        expect(config.postal.web_hostname).to eq "postal.llamas.com"
      end

      it "returns a value for postal.web_protocol" do
        expect(config.postal.web_protocol).to eq "https"
      end

      it "returns a value for postal.smtp_hostname" do
        expect(config.postal.smtp_hostname).to eq "smtp.postal.llamas.com"
      end

      it "returns a value for postal.use_ip_pools?" do
        expect(config.postal.use_ip_pools?).to eq false
      end

      it "returns a value for postal.default_maximum_delivery_attempts" do
        expect(config.postal.default_maximum_delivery_attempts).to eq 20
      end

      it "returns a value for postal.default_maximum_hold_expiry_days" do
        expect(config.postal.default_maximum_hold_expiry_days).to eq 10
      end

      it "returns a value for postal.default_suppression_list_automatic_removal_days" do
        expect(config.postal.default_suppression_list_automatic_removal_days).to eq 60
      end

      it "returns a value for postal.use_local_ns_for_domain_verification?" do
        expect(config.postal.use_local_ns_for_domain_verification?).to eq true
      end

      it "returns a value for postal.default_spam_threshold" do
        expect(config.postal.default_spam_threshold).to eq 10
      end

      it "returns a value for postal.default_spam_failure_threshold" do
        expect(config.postal.default_spam_failure_threshold).to eq 25
      end

      it "returns a value for postal.use_resent_sender_header?" do
        expect(config.postal.use_resent_sender_header?).to eq true
      end

      it "returns a value for postal.smtp_relays" do
        expect(config.postal.smtp_relays).to eq [
          { "host" => "1.2.3.4", "port" => 25, "ssl_mode" => "Auto" },
          { "host" => "2.2.2.2", "port" => 2525, "ssl_mode" => "None" },
        ]
      end
    end

    describe "the 'web_server' group" do
      it "returns a value for web_server.default_bind_address" do
        expect(config.web_server.default_bind_address).to eq "127.0.0.1"
      end

      it "returns a value for web_server.default_port" do
        expect(config.web_server.default_port).to eq 6000
      end

      it "returns a value for web_server.max_threads" do
        expect(config.web_server.max_threads).to eq 10
      end
    end

    describe "the 'main_db' group" do
      it "returns a value for main_db.host" do
        expect(config.main_db.host).to eq "localhost"
      end

      it "returns a value for main_db.port" do
        expect(config.main_db.port).to eq 3306
      end

      it "returns a value for main_db.username" do
        expect(config.main_db.username).to eq "postal"
      end

      it "returns a value for main_db.password" do
        expect(config.main_db.password).to eq "t35tpassword"
      end

      it "returns a value for main_db.database" do
        expect(config.main_db.database).to eq "postal"
      end

      it "returns a value for main_db.pool_size" do
        expect(config.main_db.pool_size).to eq 20
      end

      it "returns a value for main_db.encoding" do
        expect(config.main_db.encoding).to eq "utf8mb4"
      end
    end

    describe "the 'message_db' group" do
      it "returns a value for message_db.host" do
        expect(config.message_db.host).to eq "localhost"
      end

      it "returns a value for message_db.port" do
        expect(config.message_db.port).to eq 3306
      end

      it "returns a value for message_db.username" do
        expect(config.message_db.username).to eq "postal"
      end

      it "returns a value for message_db.password" do
        expect(config.message_db.password).to eq "p05t41"
      end

      it "returns a value for message_db.database_name_prefix" do
        expect(config.message_db.database_name_prefix).to eq "postal"
      end
    end

    describe "the 'logging' group" do
      it "returns a value for logging.rails_log_enabled" do
        expect(config.logging.rails_log_enabled).to eq true
      end
    end

    describe "the 'gelf' group" do
      it "returns a value for gelf.host" do
        expect(config.gelf.host).to eq "logs.llamas.com"
      end

      it "returns a value for gelf.port" do
        expect(config.gelf.port).to eq 12_201
      end

      it "returns a value for gelf.facility" do
        expect(config.gelf.facility).to eq "mailer"
      end
    end

    describe "the 'smtp_server' group" do
      it "returns a value for smtp_server.default_port" do
        expect(config.smtp_server.default_port).to eq 25
      end

      it "returns a value for smtp_server.default_bind_address" do
        expect(config.smtp_server.default_bind_address).to eq "127.0.0.1"
      end

      it "returns a value for smtp_server.tls_enabled" do
        expect(config.smtp_server.tls_enabled).to eq true
      end

      it "returns a value for smtp_server.tls_certificate_path" do
        expect(config.smtp_server.tls_certificate_path).to eq "config/smtp.cert"
      end

      it "returns a value for smtp_server.tls_private_key_path" do
        expect(config.smtp_server.tls_private_key_path).to eq "config/smtp.key"
      end

      it "returns a value for smtp_server.tls_ciphers" do
        expect(config.smtp_server.tls_ciphers).to eq "abc"
      end

      it "returns a value for smtp_server.ssl_version" do
        expect(config.smtp_server.ssl_version).to eq "SSLv23"
      end

      it "returns a value for smtp_server.proxy_protocol" do
        expect(config.smtp_server.proxy_protocol).to eq false
      end

      it "returns a value for smtp_server.log_connections" do
        expect(config.smtp_server.log_connections).to eq true
      end

      it "returns a value for smtp_server.max_message_size" do
        expect(config.smtp_server.max_message_size).to eq 10
      end
    end

    describe "the 'dns' group" do
      it "returns a value for dns.mx_records" do
        expect(config.dns.mx_records).to eq ["mx1.postal.llamas.com", "mx2.postal.llamas.com"]
      end

      it "returns a value for dns.spf_include" do
        expect(config.dns.spf_include).to eq "spf.postal.llamas.com"
      end

      it "returns a value for dns.return_path_domain" do
        expect(config.dns.return_path_domain).to eq "rp.postal.llamas.com"
      end

      it "returns a value for dns.route_domain" do
        expect(config.dns.route_domain).to eq "routes.postal.llamas.com"
      end

      it "returns a value for dns.track_domain" do
        expect(config.dns.track_domain).to eq "track.postal.llamas.com"
      end

      it "returns a value for dns.helo_hostname" do
        expect(config.dns.helo_hostname).to eq "helo.postal.llamas.com"
      end

      it "returns a value for dns.dkim_identifier" do
        expect(config.dns.dkim_identifier).to eq "postal"
      end

      it "returns a value for dns.domain_verify_prefix" do
        expect(config.dns.domain_verify_prefix).to eq "postal-verification"
      end

      it "returns a value for dns.custom_return_path_prefix" do
        expect(config.dns.custom_return_path_prefix).to eq "psrp"
      end
    end

    describe "the 'smtp' group" do
      it "returns a value for smtp.host" do
        expect(config.smtp.host).to eq "127.0.0.1"
      end

      it "returns a value for smtp.port" do
        expect(config.smtp.port).to eq 25
      end

      it "returns a value for smtp.username" do
        expect(config.smtp.username).to eq "postalserver"
      end

      it "returns a value for smtp.password" do
        expect(config.smtp.password).to eq "llama"
      end

      it "returns a value for smtp.from_name" do
        expect(config.smtp.from_name).to eq "Postal"
      end

      it "returns a value for smtp.from_address" do
        expect(config.smtp.from_address).to eq "[email protected]"
      end
    end

    describe "the 'rails' group" do
      it "returns a value for rails.environment" do
        expect(config.rails.environment).to eq "production"
      end

      it "returns a value for rails.secret_key" do
        expect(config.rails.secret_key).to eq "abcdef123123123123123"
      end
    end

    describe "the 'rspamd' group" do
      it "returns a value for rspamd.enabled" do
        expect(config.rspamd.enabled).to eq true
      end

      it "returns a value for rspamd.host" do
        expect(config.rspamd.host).to eq "rspamd.llamas.com"
      end

      it "returns a value for rspamd.port" do
        expect(config.rspamd.port).to eq 11_334
      end

      it "returns a value for rspamd.ssl?" do
        expect(config.rspamd.ssl?).to eq false
      end

      it "returns a value for rspamd.password" do
        expect(config.rspamd.password).to eq "llama"
      end

      it "returns a value for rspamd.flags" do
        expect(config.rspamd.flags).to eq "abc"
      end
    end

    describe "the 'spamd' group" do
      it "returns a value for spamd.enabled" do
        expect(config.spamd.enabled).to eq false
      end

      it "returns a value for spamd.host" do
        expect(config.spamd.host).to eq "spamd.llamas.com"
      end

      it "returns a value for spamd.port" do
        expect(config.spamd.port).to eq 783
      end
    end

    describe "the 'clamav' group" do
      it "returns a value for clamav.enabled" do
        expect(config.clamav.enabled).to eq false
      end

      it "returns a value for clamav.host" do
        expect(config.clamav.host).to eq "clamav.llamas.com"
      end

      it "returns a value for clamav.port" do
        expect(config.clamav.port).to eq 2000
      end
    end

    describe "the 'smtp_client' group" do
      it "returns a value for smtp_client.open_timeout" do
        expect(config.smtp_client.open_timeout).to eq 60
      end

      it "returns a value for smtp_client.read_timeout" do
        expect(config.smtp_client.read_timeout).to eq 120
      end
    end
  end

end