### Question:
VISA1Packager extends SimpleLogSource implements ISOPackager, VISA1ResponseFilter { public String guessAutNumber (String s) { StringBuilder buf = new StringBuilder(); for (int i=0; i<s.length(); i++) if (Character.isDigit(s.charAt(i))) buf.append (s.charAt(i)); if (buf.length() == 0) return null; while (buf.length() > 6) buf.deleteCharAt(0); while (buf.length() < 6) buf.insert(0, "0"); return buf.toString(); } VISA1Packager(int[] sequence, int respField, String badResultCode, String okPattern); void setVISA1ResponseFilter(VISA1ResponseFilter filter); @Override byte[] pack(ISOComponent c); String guessAutNumber(String s); @Override int unpack(ISOComponent m, byte[] b); void unpack(ISOComponent m, InputStream in); String getFieldDescription(ISOComponent m, int fldNumber); String getDescription(); ISOMsg createISOMsg(); static final byte[] FS; }### Answer:
@Test public void testGuessAutNumber() throws Throwable { int[] sequence = new int[0]; String result = new VISA1Packager(sequence, 100, "testVISA1PackagerBadResultCode", "testVISA1PackagerOkPattern") .guessAutNumber("testVISA1Packagers"); assertEquals("000001", result, "result"); }
@Test public void testGuessAutNumber1() throws Throwable { int[] sequence = new int[2]; String result = new VISA1Packager(sequence, 100, "testVISA1PackagerBadResultCode", "testVISA1PackagerOkPattern") .guessAutNumber(" "); assertNull(result, "result"); }
@Test public void testGuessAutNumber2() throws Throwable { int[] sequence = new int[2]; String result = new VISA1Packager(sequence, 100, "testVISA1PackagerBadResultCode", "testVISA1PackagerOkPattern") .guessAutNumber(""); assertNull(result, "result"); }
@Test public void testGuessAutNumber3() throws Throwable { int[] sequence = new int[1]; String result = new VISA1Packager(sequence, 100, "testVISA1PackagerBadResultCode", "testVISA1PackagerOkPattern") .guessAutNumber("1"); assertEquals("000001", result, "result"); }
@Test public void testGuessAutNumberThrowsNullPointerException() throws Throwable { int[] sequence = new int[2]; try { new VISA1Packager(sequence, 100, "testVISA1PackagerBadResultCode", "testVISA1PackagerOkPattern").guessAutNumber(null); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot invoke \"String.length()\" because \"s\" is null", ex.getMessage(), "ex.getMessage()"); } } }