### Question:
QueryUtils { public static String createSelectionPlaceholdersOfSize(int size) { if (size == 0) { return ""; } int sizeOfResult = size * 3 - 2; char[] result = new char[sizeOfResult]; for (int i = 0; i < sizeOfResult - 1; i += 3) { result[i] = '?'; result[i + 1] = ','; result[i + 2] = ' '; } result[sizeOfResult - 1] = '?'; return new String(result); }  static String createSelectionPlaceholdersOfSize(int size);  }### Answer:
@Test public void testSizeOfZeroReturnsEmptyString() { String expected = ""; assertEquals(expected, QueryUtils.createSelectionPlaceholdersOfSize(0)); }
@Test public void testSizeOfOneReturnsJustQuestionMark() { String expected = "?"; assertEquals(expected, QueryUtils.createSelectionPlaceholdersOfSize(1)); }
@Test public void testSizeBiggerThanOneReturnsSameNumberOfQuestionMarkSeparatedByCommas() { String expected = "?, ?, ?, ?, ?, ?, ?, ?, ?, ?"; assertEquals(expected, QueryUtils.createSelectionPlaceholdersOfSize(10)); }