import java.util.List;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A simplistic set which implements the bare minimum so that it can be used in tests without
 * relying on any specific Set implementations. Slow. Explicitly allows null elements so that they
 * can be used in the testers.
 *
 * @author Regina O'Dell
 */

import java.util.List;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A simplistic set which implements the bare minimum so that it can be used in tests without
 * relying on any specific Set implementations. Slow. Explicitly allows null elements so that they
 * can be used in the testers.
 *
 * @author Regina O'Dell
 */

    return key;
  }

  /**
   * Returns the current value for this system property by delegating to {@link
   * System#getProperty(String)}.
   *
   * <p>The value returned by this method is non-null except in rare circumstances:
   *
   * <ul>
   *   <li>{@link #JAVA_EXT_DIRS} was deprecated in Java 8 and removed in Java 9. We have not
   *       confirmed whether it is available under older versions.

        toolchainModels.put("rare", Collections.singletonList(new ToolchainModel()));
        executionRequest.setToolchains(toolchainModels);
        when(session.getRequest()).thenReturn(executionRequest);

        List<Toolchain> toolchains = toolchainManager.getToolchains(session, "rare", null);

        assertEquals(1, toolchains.size());
    }

    @Test

        List<ToolchainModel> rareToolchains = new ArrayList<>();
        ToolchainModel rareToolchainModel = new ToolchainModel();
        rareToolchainModel.setType("rare");
        rareToolchains.add(rareToolchainModel);
        groupedToolchains.put("rare", rareToolchains);

        // execute
        ToolchainPrivate[] toolchains = toolchainManager.getToolchainsForType("basic", session);

        // verify

    g2.addEdge(N1, N3, E12);

    assertThat(network).isNotEqualTo(g2);
  }

  // Node/edge sets and node/edge connections are the same, but network properties differ.
  // (In this case the networks are considered equivalent; the property differences are irrelevant.)
  @Test
  public void equivalent_propertiesDiffer() {
    network.addEdge(N1, N2, E12);

    MutableNetwork<Integer, String> g2 =

    g2.putEdge(N1, N1);

    assertThat(graph).isNotEqualTo(g2);
  }

  // Node/edge sets and node/edge connections are the same, but graph properties differ.
  // In this case the graphs are considered equivalent; the property differences are irrelevant.
  @Test
  public void equivalent_propertiesDiffer() {
    graph.putEdge(N1, N2);

    MutableGraph<Integer> g2 =

  int getHash();

  /** Returns the key for this entry. */
  @CheckForNull
  K getKey();

  /*
   * Used by entries that use access order. Access entries are maintained in a doubly-linked list.
   * New entries are added at the tail of the list at write time; stale entries are expired from
   * the head of the list.
   */

  /** Returns the time that this entry was last accessed, in ns. */
  @SuppressWarnings("GoodTime")

    Escapers.Builder builder = Escapers.builder();
    // The char values \uFFFE and \uFFFF are explicitly not allowed in XML
    // (Unicode code points above \uFFFF are represented via surrogate pairs
    // which means they are treated as pairs of safe characters).
    builder.setSafeRange(Character.MIN_VALUE, '\uFFFD');
    // Unsafe characters are replaced with the Unicode replacement character.
    builder.setUnsafeReplacement("\uFFFD");

    protected int attributes;

/* This filter can be considerably more efficient than other file filters
 * as the specifed wildcard and attributes are passed to the server for
 * filtering there (although attributes are largely ignored by servers
 * they are filtered locally by the default accept method).
 */
    public DosFileFilter( String wildcard, int attributes ) {
        this.wildcard = wildcard;