recursivelyCompareDirectories

recursivelyCompareDirectories.java

  /**
     * Recursively compare the contents of the directory of downloaded
     * files with the contents of the "ground truth" directory.
     */
    public static void recursivelyCompareDirectories(File expected,
                                               File generated)
            throws IOException {
        // Checks parameters.
        assertTrue("Generated Folder doesn't exist: " + generated,
                generated.exists());
        assertTrue("Generated is not a folder?!?!: " + generated,
                generated.isDirectory());

        assertTrue("Expected Folder doesn't exist: " + expected,
                expected.exists());
        assertTrue("Expected is not a folder?!?!: " + expected,
                expected.isDirectory());

        Files.walkFileTree(expected.toPath(),
                new SimpleFileVisitor<Path>() {
                    @Override
                    public FileVisitResult preVisitDirectory(Path dir,
                                                             BasicFileAttributes attrs)
                            throws IOException {
                        FileVisitResult result =
                                super.preVisitDirectory(dir, attrs);

                        // Get the relative file name from
                        // path "expected"
                        Path relativize =
                                expected.toPath().relativize(dir);

                        // Construct the path for the
                        // counterpart file in "generated"
                        File otherDir =
                                generated.toPath().resolve(relativize).toFile();

                        assertEquals("Folders doesn't contain same file!?!?",
                                Arrays.toString(dir.toFile().list()),
                                Arrays.toString(otherDir.list()));
                        return result;
                    }

                    @Override
                    public FileVisitResult visitFile(Path file,
                                                     BasicFileAttributes attrs)
                            throws IOException {
                        FileVisitResult result =
                                super.visitFile(file, attrs);

                        // Get the relative file name from
                        // path "expected".
                        Path relativize =
                                expected.toPath().relativize(file);

                        // Construct the path for the
                        // counterpart file in "generated".
                        Path fileInOther =
                                generated.toPath().resolve(relativize);

                        byte[] otherBytes = Files.readAllBytes(fileInOther);
                        byte[] thisBytes = Files.readAllBytes(file);

                        if (!Arrays.equals(otherBytes, thisBytes))
                            throw new AssertionFailedError(file + " is not equal to " + fileInOther);

                        return result;
                    }
                });
    }