Moved from logger double to real log spy using log4j appender in SettingWithDeprecatedAlias spec test.

Author: andsel

logstash-core/spec/logstash/settings/setting_with_deprecated_alias_spec.rb

@@ -25,7 +25,16 @@
   let(:default_value) { "DeFaUlT" }
 
   let(:settings) { LogStash::Settings.new }
-  let(:canonical_setting) { LogStash::Setting::String.new(canonical_setting_name, default_value, true) }
+  let(:canonical_setting) { LogStash::Setting::StringSetting.new(canonical_setting_name, default_value, true) }
+
+  let(:log_ctx) { setup_logger_spy }
+  let(:log_spy) { retrieve_logger_spy(log_ctx) }
+
+  before(:each) do
+    # Initialization of appender and logger use to spy, need to be done before executing any code that logs,
+    # that's the reason wy to refer the spying logger context before any test.
+    log_ctx
+  end
 
   before(:each) do
     allow(LogStash::Settings).to receive(:logger).and_return(double("SettingsLogger").as_null_object)
@@ -57,6 +66,8 @@
       it 'does not emit a deprecation warning' do
         expect(LogStash::Settings.deprecation_logger).to_not receive(:deprecated).with(a_string_including(deprecated_setting_name))
         settings.get_setting(deprecated_setting_name).observe_post_process
+        log_spy = retrieve_logger_spy(log_ctx)
+        expect(log_spy.messages).to be_empty
       end
     end
   end
@@ -66,22 +77,23 @@
 
     before(:each) do
       settings.set(deprecated_setting_name, value)
+      settings.get_setting(deprecated_setting_name).observe_post_process
     end
 
     it 'resolves to the value provided for the deprecated alias' do
       expect(settings.get(canonical_setting_name)).to eq(value)
     end
 
     it 'logs a deprecation warning' do
-      expect(LogStash::Settings.deprecation_logger).to have_received(:deprecated).with(a_string_including(deprecated_setting_name))
+      expect(log_spy.messages[0]).to include(deprecated_setting_name)
     end
 
     include_examples '#validate_value success'
 
     context "#observe_post_process" do
       it 're-emits the deprecation warning' do
-        expect(LogStash::Settings.deprecation_logger).to receive(:deprecated).with(a_string_including(deprecated_setting_name))
         settings.get_setting(deprecated_setting_name).observe_post_process
+        expect(log_spy.messages[0]).to include(deprecated_setting_name)
       end
     end
 
@@ -149,15 +161,16 @@
     end
 
     it 'does not produce a relevant deprecation warning' do
-      expect(LogStash::Settings.deprecation_logger).to_not have_received(:deprecated).with(a_string_including(deprecated_setting_name))
+      settings.get_setting(deprecated_setting_name).observe_post_process
+      expect(log_spy.messages).to be_empty
     end
 
     include_examples '#validate_value success'
 
     context "#observe_post_process" do
       it 'does not emit a deprecation warning' do
-        expect(LogStash::Settings.deprecation_logger).to_not receive(:deprecated).with(a_string_including(deprecated_setting_name))
         settings.get_setting(deprecated_setting_name).observe_post_process
+        expect(log_spy.messages).to be_empty
       end
     end
   end
@@ -171,15 +184,15 @@
     context '#validate_value' do
       it "raises helpful exception" do
         expect { settings.get_setting(canonical_setting_name).validate_value }
-          .to raise_exception(ArgumentError, a_string_including("Both `#{canonical_setting_name}` and its deprecated alias `#{deprecated_setting_name}` have been set. Please only set `#{canonical_setting_name}`"))
+          .to raise_exception(java.lang.IllegalStateException, a_string_including("Both `#{canonical_setting_name}` and its deprecated alias `#{deprecated_setting_name}` have been set. Please only set `#{canonical_setting_name}`"))
       end
     end
   end
 
   context 'Settings#get on deprecated alias' do
     it 'produces a WARN-level message to the logger' do
-      expect(LogStash::Settings.logger).to receive(:warn).with(a_string_including "setting `#{canonical_setting_name}` has been queried by its deprecated alias `#{deprecated_setting_name}`")
       settings.get(deprecated_setting_name)
+      expect(log_spy.messages[0]).to include("setting `#{canonical_setting_name}` has been queried by its deprecated alias `#{deprecated_setting_name}`")
     end
   end
 end

spec/spec_helper.rb

@@ -90,3 +90,40 @@ def puts(payload)
 def installed_plugins
   Gem::Specification.find_all.select { |spec| spec.metadata["logstash_plugin"] }.map { |plugin| plugin.name }
 end
+
+
+def setup_logger_spy
+  java_import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory
+  java_import org.apache.logging.log4j.Level
+  config_builder = ConfigurationBuilderFactory.newConfigurationBuilder
+  configure_log_spy = config_builder
+                        .add(
+                          config_builder
+                            .newAppender("LOG_SPY", "List")
+                            .add(config_builder.newLayout("PatternLayout").addAttribute("pattern", "%-5p [%t]: %m%n"))
+                        )
+                        .add(
+                          config_builder
+                            .newRootLogger(Level::INFO)
+                            .add(config_builder.newAppenderRef("LOG_SPY")))
+                        .build(false)
+
+  java_import org.apache.logging.log4j.core.config.Configurator
+  java_import org.apache.logging.log4j.core.config.Configuration
+
+  java_import org.apache.logging.log4j.LogManager
+  java_import org.apache.logging.log4j.core.impl.Log4jContextFactory
+  # This is done because the LoggerExt calls setFactory LogstashLoggerContextFactory implements
+  # org.apache.logging.log4j.spi.LoggerContextFactory and doesn't extend org.apache.logging.log4j.core.impl.Log4jContextFactory
+  # which is the class expected by the following Configurator to use the programmatic configuration.
+  LogManager.setFactory(Log4jContextFactory.new)
+  log_ctx = Configurator.java_send(:initialize, [Configuration], configure_log_spy)
+  expect(log_ctx).not_to be nil
+  log_ctx.reconfigure(configure_log_spy) # force the programmatic configuration, without this it's not used
+
+  return log_ctx
+end
+
+def retrieve_logger_spy(log_ctx)
+  log_ctx.getConfiguration().getAppender("LOG_SPY")
+end