/**
     * GETs the source URI content into target (does not have to exist, or will be overwritten if exist). The
     * source MUST BE relative from the {@link RemoteRepository#getUrl()} root.
     *
     * @return {@code true} if operation succeeded, {@code false} if source does not exist.
     * @throws RuntimeException If failed (and not due source not exists).
     */
    boolean get(@Nonnull URI relativeSource, @Nonnull Path target);

  static final String EDGE_ALREADY_EXISTS = "Edge %s already exists in the graph.";
  static final String ENDPOINTS_MISMATCH =
      "Mismatch: endpoints' ordering is not compatible with directionality of the graph";

  /** Singleton edge value for {@link Graph} implementations backed by {@link ValueGraph}s. */
  enum Presence {
    EDGE_EXISTS
  }

  }

  private interface HierarchyFixtureInterface {
    // Exists only for hierarchy mapping; no members.
  }

  private interface HierarchyFixtureSubinterface extends HierarchyFixtureInterface {
    // Exists only for hierarchy mapping; no members.
  }

  private static class HierarchyFixtureParent implements HierarchyFixtureSubinterface {
    // Exists only for hierarchy mapping; no members.
  }

                boolean exists = installed.stream().map(this::getArtifactFromMap)
                        .anyMatch(a -> a.getName().equals(target.getName()) && a.getVersion().equals(target.getVersion()));
                if (!exists) {
                    ThreadUtil.sleep(500);
                    continue;
                }
                assertTrue(exists);
                done = true;
                break;

    public void assertFileExistence(File dir, String filename, boolean shouldExist) {
        File file = new File(dir, filename);

        if (shouldExist) {
            assertTrue(file.exists());
        } else {
            assertFalse(file.exists());
        }
    }

    public void assertFileContents(File dir, String filename, String contentsTest, String encoding) throws IOException {

        "The process cannot access the file because another process has locked a portion of the file.", "The disk is full.",
        "A duplicate name exists on the network.", "The network name cannot be found.", "ERRnomoreconn.", "The file exists.",
        "The parameter is incorrect.", "Too many Uids active on this session.", "The Uid is not known as a valid user identifier on this session.",

        if (file == null) {
            throw new FileAccessException("ECL0108");
        }

        this.propertiesFile = file;
        if (!this.propertiesFile.exists()) {
            final File parentDir = this.propertiesFile.getParentFile();
            if (!parentDir.exists()) {
                if (!parentDir.mkdir()) {
                    throw new FileAccessException("ECL0109", new Object[] { file.getAbsolutePath() });
                }

                .globalToolchainsSource(
                        globalToolchainsPath != null && Files.exists(globalToolchainsPath)
                                ? Source.fromPath(globalToolchainsPath)
                                : null)
                .userToolchainsSource(
                        userToolchainsPath != null && Files.exists(userToolchainsPath)
                                ? Source.fromPath(userToolchainsPath)

        }

        if (outputFile.exists()) {
            if (logger.isDebugEnabled()) {
                logger.debug("The thumbnail file exists: {}", outputFile.getAbsolutePath());
            }
            return true;
        }

        final File parentFile = outputFile.getParentFile();
        if (!parentFile.exists()) {
            parentFile.mkdirs();
        }

            if (className.contains(appWebPkg) && className.endsWith(actionSuffix)) {
                // ## Assert ##
                markHere("exists");
                getComponent(clazz); // expect no exception
            }
        });
        assertMarked("exists");
    }
    */

    // ===================================================================================