public void CanAddAndRemoveHandlers()
{
SystemConfigurationSourceImplementation implementation = new SystemConfigurationSourceImplementation(false);
object section = implementation.GetSection(externalSection);
Assert.IsNotNull(section);
implementation.AddSectionChangeHandler(externalSection, new ConfigurationChangedEventHandler(OnConfigurationChanged));
implementation.AddSectionChangeHandler(externalSection, new ConfigurationChangedEventHandler(OnConfigurationChanged));
implementation.ExternalConfigSourceChanged(externalSectionSource);
Assert.AreEqual(2, updatedSectionsTally[externalSection]);
implementation.RemoveSectionChangeHandler(externalSection, new ConfigurationChangedEventHandler(OnConfigurationChanged));
implementation.ExternalConfigSourceChanged(externalSectionSource);
Assert.AreEqual(3, updatedSectionsTally[externalSection]);
implementation.RemoveSectionChangeHandler(externalSection, new ConfigurationChangedEventHandler(OnConfigurationChanged));
implementation.ExternalConfigSourceChanged(externalSectionSource);
Assert.AreEqual(3, updatedSectionsTally[externalSection]);
}