package com.atlassian.sal.core.features;
   
   import org.junit.rules.TestWatcher;
   import org.junit.runner.Description;
   
   import javax.annotation.Nonnull;
   import java.util.HashSet;
   import java.util.Set;
   
  /**
   * All system properties set through this rule are guaranteed to be cleaned up after the test method has finished.
   */
  public class ClearSystemPropertyRule extends TestWatcher
  {
      private final Set<String> properties = new HashSet<String>();
  
      /**
       * Set a system property key to the given value. The system property will be cleared when the test finishes.
       * @param key the system property to be set
       * @param value the value to be associated with the system property
       */
      public void setProperty(@Nonnull final String key, @Nonnull final String value)
      {
          properties.add(key);
          System.setProperty(key, value);
      }
  
      /**
       * Set a system property key to the given value. Will always put the {@link DefaultDarkFeatureManager#ATLASSIAN_DARKFEATURE_PREFIX}
       * in for you.
       *
       * @param key the system property to be set. Will be effectively: {@link DefaultDarkFeatureManager#ATLASSIAN_DARKFEATURE_PREFIX} + key
       * @param value the value to be set
       */
      public void setPropertyWithDarkFeaturePrefix(@Nonnull final String key, @Nonnull final String value)
      {
          setProperty(DefaultDarkFeatureManager.ATLASSIAN_DARKFEATURE_PREFIX + key, value);
      }
  
      @Override
      protected void finished(final Description description)
      {
          for (final String property : properties)
          {
              System.clearProperty(property);
          }
      }
  }