### Question:
Helper { static public String getDisplayAmount(long amount) { return getDisplayAmount(amount, 12); }  static File getWalletRoot(Context context); static File getStorage(Context context, String folderName); static boolean getWritePermission(Activity context); static boolean getCameraPermission(Activity context); static File getWalletFile(Context context, String aWalletName); static void showKeyboard(Activity act); static void hideKeyboard(Activity act); static void showKeyboard(Dialog dialog); static void hideKeyboardAlways(Activity act); static BigDecimal getDecimalAmount(long amount); static String getDisplayAmount(long amount); static String getDisplayAmount(long amount, int maxDecimals); static String getFormattedAmount(double amount, boolean isCrypto); static String getFormattedAmount(double amount); static Bitmap getBitmap(Context context, int drawableId); static String getUrl(String httpsUrl); static void clipBoardCopy(Context context, String label, String text); static String getClipBoardText(Context context); static Animation getShakeAnimation(Context context); static HttpUrl getXmrToBaseUrl(); static String bytesToHex(byte[] data); static byte[] hexToBytes(String hex); static void setMoneroHome(Context context); static void initLogger(Context context); static void initLogger(Context context, int level); static boolean useCrazyPass(Context context); static String getWalletPassword(Context context, String walletName, String password); static void promptPassword(final Context context, final String wallet, boolean fingerprintDisabled, final PasswordAction action); static ExchangeApi getExchangeApi(); static boolean runWithNetwork(Action action); static boolean preventScreenshot(); static final String NOCRAZYPASS_FLAGFILE; static final String BASE_CRYPTO; static public int DISPLAY_DIGITS_INFO; static final int PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE; static final int PERMISSIONS_REQUEST_CAMERA; }### Answer:
@Test public void testMinus() { long l = -1000000000000L; String s = Helper.getDisplayAmount(l, 5); System.out.println(s); assertTrue(s.equals("-1.00")); }
@Test public void testTen() { long l = 10L; String s = Helper.getDisplayAmount(l); System.out.println(s); assertTrue(s.equals("0.00000000001")); }
@Test public void testZero() { long l = 0L; String s = Helper.getDisplayAmount(l); System.out.println(s); assertTrue(s.equals("0.00")); }
@Test public void testG() { long l = 1234567891234L; String s = Helper.getDisplayAmount(l); System.out.println(s); assertTrue(s.equals("1.234567891234")); }
@Test public void testG2() { long l = 1000000000000L; String s = Helper.getDisplayAmount(l); System.out.println(s); assertTrue(s.equals("1.00")); }
@Test public void testE() { long l = 1234567891234L; String s = Helper.getDisplayAmount(l, 4); System.out.println(s); assertTrue(s.equals("1.2346")); }
@Test public void testF() { long l = 1234567891234L; String s = Helper.getDisplayAmount(l, 12); System.out.println(s); assertTrue(s.equals("1.234567891234")); }
@Test public void testH() { long l = 1004567891234L; String s = Helper.getDisplayAmount(l, 2); System.out.println(s); assertTrue(s.equals("1.00")); }