NoopDescriptor.java

/*
** Module   : NoopDescriptor.java
** Abstract : Test descriptor which does nothing.
**
** Copyright (c) 2023-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description---------------------------------
** 001 VVT 20230318 Created initial version.
** 002 VVT 20240321 Access to the parent test descriptor field changed to protected. See #8406.
** 003 VVT 20240614 The class now implements Node<FWDEngineExecutionContext>, and the execute()
**                  method always throws an exception. See #8529. 
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
** 
**   0. Attribution Requirement.
** 
**     You must preserve all legal notices or author attributions in the covered
**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
**     credit already included within the covered work.
** 
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** 
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*/
package com.goldencode.p2j.testengine;

import java.io.*;
import java.util.*;

import org.junit.platform.commons.util.*;
import org.junit.platform.engine.*;
import org.junit.platform.engine.support.hierarchical.*;

import com.goldencode.util.*;

/**
 * The {@link NoopDescriptor} does nothing.
 */
public class NoopDescriptor
implements Node<FWDEngineExecutionContext>,
           TestDescriptor,
           Printable,
           Externalizable
{

   /** This descriptor display name */
   private String displayName;

   /** The descriptor unique ID */
   private UniqueId uniqueId;

   /** The parent descriptor or {@code null} if this is the root (test engine) descriptor */
   protected TestDescriptor parent;

   /**
    * The constructor.
    * 
    * @param uniqueId
    *        the descriptor unique ID
    * @param displayName
    *        the descriptor display name
    */
   public NoopDescriptor(final UniqueId uniqueId, final String displayName)
   {
      this.displayName = displayName;
      this.uniqueId = uniqueId;
   }

   /**
    * Add a <em>child</em> to this descriptor.
    * 
    * @param descriptor the child to add to this descriptor; never {@code null}
    */
   @Override
   public void addChild(TestDescriptor descriptor)
   {
      // Default is the terminal node implementation, must be re-defined for branch nodes
      throw new RuntimeException("Not supported");
   }

   /**
    * Indicates whether some other object is "equal to" this one.
    * <p>
    * The {@code equals} method implements an equivalence relation
    * on non-null object references:
    * <ul>
    * <li>It is <i>reflexive</i>: for any non-null reference value
    * {@code x}, {@code x.equals(x)} should return
    * {@code true}.
    * <li>It is <i>symmetric</i>: for any non-null reference values
    * {@code x} and {@code y}, {@code x.equals(y)}
    * should return {@code true} if and only if
    * {@code y.equals(x)} returns {@code true}.
    * <li>It is <i>transitive</i>: for any non-null reference values
    * {@code x}, {@code y}, and {@code z}, if
    * {@code x.equals(y)} returns {@code true} and
    * {@code y.equals(z)} returns {@code true}, then
    * {@code x.equals(z)} should return {@code true}.
    * <li>It is <i>consistent</i>: for any non-null reference values
    * {@code x} and {@code y}, multiple invocations of
    * {@code x.equals(y)} consistently return {@code true}
    * or consistently return {@code false}, provided no
    * information used in {@code equals} comparisons on the
    * objects is modified.
    * <li>For any non-null reference value {@code x},
    * {@code x.equals(null)} should return {@code false}.
    * </ul>
    * <p>
    * The {@code equals} method for class {@code Object} implements
    * the most discriminating possible equivalence relation on objects;
    * that is, for any non-null reference values {@code x} and
    * {@code y}, this method returns {@code true} if and only
    * if {@code x} and {@code y} refer to the same object
    * ({@code x == y} has the value {@code true}).
    * <p>
    * Note that it is generally necessary to override the {@code hashCode}
    * method whenever this method is overridden, so as to maintain the
    * general contract for the {@code hashCode} method, which states
    * that equal objects must have equal hash codes.
    * 
    * @param  obj   the reference object with which to compare.
    * 
    * @return {@code true} if this object is the same as the obj
    *         argument; {@code false} otherwise.
    * 
    * @see    #hashCode()
    * @see    java.util.HashMap
    */
   @Override
   public final boolean equals(Object obj)
   {
      // Test descriptors are compared by their unique IDs.
      if (obj == null)
      {
         return false;
      }
   
      if (this.getClass() != obj.getClass())
      {
         return false;
      }
   
      return uniqueId.equals(((TestDescriptor) obj).getUniqueId());
   }

   /**
    * Execute the <em>behavior</em> of this node.
    *
    * <p>Containers typically do not implement this method since the
    * {@link HierarchicalTestEngine} handles execution of their children.
    *
    * <p>The supplied {@code dynamicTestExecutor} may be used to submit
    * additional dynamic tests for immediate execution.
    *
    * <p>The default implementation returns the supplied {@code context} unmodified.
    *
    * @param context the context to execute in
    * @param dynamicTestExecutor the executor to submit dynamic tests to
    * @return the new context to be used for children of this node and for the
    * <em>after</em> behavior of the parent of this node, if any
    * @see #before
    * @see #after
    */
   @Override
   public FWDEngineExecutionContext execute(FWDEngineExecutionContext context,
                                            DynamicTestExecutor dynamicTestExecutor)
   throws Exception
   {
      // Instances of this very class are created in case of failed test engine initialization.
      // The tests in this case must always fail.
      throw new Exception("Test engine was not initialized.");
   }

   /**
    * Find the descriptor with the supplied unique ID.
    * <p>
    * The search algorithm begins with this descriptor and then searches
    * through its descendants.
    * 
    * @param id the {@code UniqueId} to search for; never {@code null}
    */
   @Override
   public Optional<? extends TestDescriptor> findByUniqueId(final UniqueId id)
   {
      return Optional.of(this.uniqueId.equals(id) ? this : null);
   }

   /**
    * Get the immutable set of <em>children</em> of this descriptor.
    * 
    * @return the set of children of this descriptor; neither {@code null}
    *         nor mutable, but potentially empty
    * 
    * @see    #getDescendants()
    */
   @Override
   public Set<? extends TestDescriptor> getChildren()
   {
      return Collections.emptySet();
   }

   /**
    * Get the display name for this descriptor.
    * <p>
    * A <em>display name</em> is a human-readable name for a test or
    * container that is typically used for test reporting in IDEs and build
    * tools. Display names may contain spaces, special characters, and emoji,
    * and the format may be customized by {@link TestEngine TestEngines} or
    * potentially by end users as well. Consequently, display names should
    * never be parsed; rather, they should be used for display purposes only.
    * 
    * @return the display name for this descriptor; never {@code null} or blank
    * 
    * @see    #getSource()
    */
   @Override
   public String getDisplayName()
   {
      return displayName;
   }

   /**
    * Get the <em>parent</em> of this descriptor, if available.
    */
   @Override
   public Optional<TestDescriptor> getParent()
   {
      return Optional.ofNullable(parent);
   }

   /**
    * Get the {@linkplain TestSource source} of the test or container described
    * by this descriptor, if available.
    * 
    * @see TestSource
    */
   @Override
   public Optional<TestSource> getSource()
   {
      return Optional.empty();
   }

   /**
    * Get the set of {@linkplain TestTag tags} associated with this descriptor.
    * 
    * @return the set of tags associated with this descriptor; never {@code null}
    *         but potentially empty
    * 
    * @see    TestTag
    */
   @Override
   public Set<TestTag> getTags()
   {
      // tags are not used in FWD test engine currently
      return Collections.emptySet();
   }

   /**
    * Determine the {@link org.junit.platform.engine.TestDescriptor.Type} of this descriptor.
    * 
    * @return the descriptor type; never {@code null}.
    * 
    * @see    #isContainer()
    * @see    #isTest()
    */
   @Override
   public Type getType()
   {
      // Default value, test containers must re-define this method 
      return Type.TEST;
   }

   /**
    * Get the unique identifier (UID) for this descriptor.
    * <p>
    * Uniqueness must be guaranteed across an entire test plan,
    * regardless of how many engines are used behind the scenes.
    * 
    * @return the {@code UniqueId} for this descriptor; never {@code null}
    */
   @Override
   public final UniqueId getUniqueId()
   {
      return this.uniqueId;
   }

   /**
    * Returns a hash code value for the object. This method is
    * supported for the benefit of hash tables such as those provided by
    * {@link java.util.HashMap}.
    * <p>
    * The general contract of {@code hashCode} is:
    * <ul>
    * <li>Whenever it is invoked on the same object more than once during
    * an execution of a Java application, the {@code hashCode} method
    * must consistently return the same integer, provided no information
    * used in {@code equals} comparisons on the object is modified.
    * This integer need not remain consistent from one execution of an
    * application to another execution of the same application.
    * <li>If two objects are equal according to the {@code equals(Object)}
    * method, then calling the {@code hashCode} method on each of
    * the two objects must produce the same integer result.
    * <li>It is <em>not</em> required that if two objects are unequal
    * according to the {@link java.lang.Object#equals(java.lang.Object)}
    * method, then calling the {@code hashCode} method on each of the
    * two objects must produce distinct integer results.  However, the
    * programmer should be aware that producing distinct integer results
    * for unequal objects may improve the performance of hash tables.
    * </ul>
    * <p>
    * As much as is reasonably practical, the hashCode method defined by
    * class {@code Object} does return distinct integers for distinct
    * objects. (This is typically implemented by converting the internal
    * address of the object into an integer, but this implementation
    * technique is not required by the
    * Java&trade; programming language.)
    * 
    * @return a hash code value for this object.
    * 
    * @see    java.lang.Object#equals(java.lang.Object)
    * @see    java.lang.System#identityHashCode
    */
   @Override
   public final int hashCode()
   {
      return uniqueId.hashCode();
   }

   /**
    * Print all class-specific fields.
    * 
    * @param printer
    *        the string printer to print into
    */
   @Override
   public void print(PrintHelper printer)
   {
      printer.print(uniqueId);
      printer.print(displayName);
   
      if (parent != null)
      {
         printer.print(parent.getDisplayName());
      }
   }

   /**
    * The object implements the readExternal method to restore its
    * contents by calling the methods of DataInput for primitive
    * types and readObject for objects, strings and arrays.  The
    * readExternal method must read the values in the same sequence
    * and with the same types as were written by writeExternal.
    * 
    * @param     in the stream to read data from in order to restore the object
    * 
    * @exception IOException if I/O errors occur
    * @exception ClassNotFoundException If the class for an object being
    *            restored cannot be found.
    */
   @Override
   public void readExternal(ObjectInput in)
   throws IOException,
          ClassNotFoundException
   {
      uniqueId = (UniqueId) in.readObject();
      displayName = (String) in.readObject();
   }

   /**
    * Remove a <em>child</em> from this descriptor.
    * 
    * @param descriptor the child to remove from this descriptor; never
    *        {@code null}
    */
   @Override
   public void removeChild(TestDescriptor descriptor)
   {
      throw new RuntimeException("Not supported");
   }

   /**
    * Remove this non-root descriptor from its parent and remove all the
    * children from this descriptor.
    * <p>
    * If this method is invoked on a {@linkplain #isRoot root} descriptor,
    * this method must throw a {@link org.junit.platform.commons.JUnitException JUnitException}
    * explaining that a root cannot be removed from the
    * hierarchy.
    */
   @Override
   public void removeFromHierarchy()
   {
      Preconditions.condition(!isRoot(), "cannot remove the root of a hierarchy");
      
      parent.removeChild(this);
      setParent(null);
   }

   /**
    * Set the <em>parent</em> of this descriptor.
    * 
    * @param parent the new parent of this descriptor; may be {@code null}.
    */
   @Override
   public void setParent(final TestDescriptor parent)
   {
      this.parent = parent;
   }

   /**
    * Returns a string representation of the object. In general, the
    * {@code toString} method returns a string that
    * "textually represents" this object. The result should
    * be a concise but informative representation that is easy for a
    * person to read.
    * It is recommended that all subclasses override this method.
    * <p>
    * The {@code toString} method for class {@code Object}
    * returns a string consisting of the name of the class of which the
    * object is an instance, the at-sign character `{@code @}', and
    * the unsigned hexadecimal representation of the hash code of the
    * object. In other words, this method returns a string equal to the
    * value of:
    * <blockquote>
    * <pre>
    * getClass().getName() + '@' + Integer.toHexString(hashCode())
    * </pre></blockquote>
    * 
    * @return a string representation of the object.
    */
   @Override
   public String toString()
   {
      return asString();
   }

   /**
    * The object implements the writeExternal method to save its contents
    * by calling the methods of DataOutput for its primitive values or
    * calling the writeObject method of ObjectOutput for objects, strings,
    * and arrays.
    * 
    * @serialData Overriding methods should use this tag to describe
    *             the data layout of this Externalizable object.
    *             List the sequence of element types and, if possible,
    *             relate the element to a public/protected field and/or
    *             method of this Externalizable class.
    * 
    * @param      out the stream to write the object to
    * 
    * @exception  IOException Includes any I/O exceptions that may occur
    */
   @Override
   public void writeExternal(ObjectOutput out)
   throws IOException
   {
      out.writeObject(uniqueId);
      out.writeObject(displayName);
   }

}