### Question:
LogSegmentNameHelper { static String nameFromFilename(String filename) { if (filename.equals(SINGLE_SEGMENT_LOG_FILE_NAME)) { return ""; } if (!filename.endsWith(SUFFIX)) { throw new IllegalArgumentException("The filename of the log segment does not end with [" + SUFFIX + "]"); } String name = filename.substring(0, filename.length() - SUFFIX.length()); validate(name); return name; }    }### Answer:
@Test public void nameFromFilenameTest() { assertEquals("Did not get expected name", "", LogSegmentNameHelper.nameFromFilename("log_current")); String name = LogSegmentNameHelper.getName(0, 0); String filename = LogSegmentNameHelper.nameToFilename(name); assertEquals("Did not get expected name", name, LogSegmentNameHelper.nameFromFilename(filename)); String badNameBase = TestUtils.getRandomString(10); String[] badNames = {badNameBase, badNameBase + LogSegmentNameHelper.SUFFIX, name + BlobStore.SEPARATOR + "123" + LogSegmentNameHelper.SUFFIX}; for (String badName : badNames) { try { LogSegmentNameHelper.nameFromFilename(badName); fail("Should have failed to get name for filename [" + badName + "]"); } catch (IllegalArgumentException | StringIndexOutOfBoundsException e) { } } }