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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.server.wifi.util;
     18 
     19 import static org.junit.Assert.assertFalse;
     20 import static org.junit.Assert.assertTrue;
     21 
     22 import android.support.test.filters.SmallTest;
     23 
     24 import org.junit.Test;
     25 
     26 /**
     27  * Unit tests for {@link com.android.server.wifi.util.StringUtil}.
     28  */
     29 @SmallTest
     30 public class StringUtilTest {
     31     static final byte ASCII_UNIT_SEPARATOR = 31;
     32     static final byte ASCII_DEL = 127;
     33 
     34     /** Verifies that isAsciiPrintable() does not crash when passed a null array. */
     35     @Test
     36     public void nullArrayDoesNotCauseCrash() {
     37         assertTrue(StringUtil.isAsciiPrintable(null));
     38     }
     39 
     40     /** Verifies that isAsciiPrintable() considers an empty array to be printable. */
     41     @Test
     42     public void emptyArrayIsPrintable() {
     43         assertTrue(StringUtil.isAsciiPrintable(new byte[]{}));
     44     }
     45 
     46     /** Verifies that isAsciiPrintable() considers a single printable byte to be printable. */
     47     @Test
     48     public void arrayWithSinglePrintableByteIsPrintable() {
     49         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'a'}));
     50     }
     51 
     52     /**
     53      * Verifies that isAsciiPrintable() considers an array of multiple printable bytes to be
     54      * printable.
     55      */
     56     @Test
     57     public void arrayWithMultiplePrintableBytesIsPrintable() {
     58         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'a', 'b'}));
     59     }
     60 
     61     /**
     62      * Verifies that isAsciiPrintable() considers bell, form feed, newline, horizontal tab,
     63      * and vertical tab to be printable.
     64      */
     65     @Test
     66     public void printableControlCharactersAreConsideredPrintable() {
     67         assertTrue(StringUtil.isAsciiPrintable(new byte[]{0x07}));  // bell
     68         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\f'}));  // form feed
     69         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\n'}));
     70         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\t'}));
     71         assertTrue(StringUtil.isAsciiPrintable(new byte[]{0x0b}));  // vertical tab
     72     }
     73 
     74     /** Verifies that isAsciiPrintable() considers a newline to be printable. */
     75     @Test
     76     public void arrayWithNewlineIsPrintable() {
     77         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'\n'}));
     78     }
     79 
     80     /** Verifies that isAsciiPrintable() considers a space to be printable. */
     81     @Test
     82     public void arrayWithSpaceIsPrintable() {
     83         assertTrue(StringUtil.isAsciiPrintable(new byte[]{' '}));
     84     }
     85 
     86     /** Verifies that isAsciiPrintable() considers a tilde to be printable. */
     87     @Test
     88     public void arrayWithTildeIsPrintable() {
     89         assertTrue(StringUtil.isAsciiPrintable(new byte[]{'~'}));
     90     }
     91 
     92     /** Verifies that isAsciiPrintable() considers a null to be unprintable. */
     93     @Test
     94     public void arrayWithNullByteIsNotPrintable() {
     95         assertFalse(StringUtil.isAsciiPrintable(new byte[]{0}));
     96     }
     97 
     98     /** Verifies that isAsciiPrintable() considers (space-1) to be unprintable. */
     99     @Test
    100     public void arrayWithUnitSeparatorIsNotPrintable() {
    101         assertFalse(StringUtil.isAsciiPrintable(new byte[]{ASCII_UNIT_SEPARATOR}));
    102     }
    103 
    104     /** Verifies that isAsciiPrintable() considers (tilde+1) to be unprintable. */
    105     @Test
    106     public void arrayWithDelIsNotPrintable() {
    107         assertFalse(StringUtil.isAsciiPrintable(new byte[]{ASCII_DEL}));
    108     }
    109 
    110     /**
    111      * Verifies that isAsciiPrintable() considers negative bytes to be unprintable.
    112      * (In unsigned representation, these are values greater than DEL.)
    113      */
    114     @Test
    115     public void arrayWithNegativeByteIsNotPrintable() {
    116         assertFalse(StringUtil.isAsciiPrintable(new byte[]{-128}));
    117         assertFalse(StringUtil.isAsciiPrintable(new byte[]{-1}));
    118     }
    119 }
    120