add UT with timeout for Text#find and fix comments

Author: xinqiu.hu

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/Text.java

@@ -200,7 +200,7 @@ public int find(String what, int start) {
           while (tgt.hasRemaining()) {
             if (!src.hasRemaining()) { // src expired first
               // the remaining bytes in src will always smaller than tgt,
-              // so we can return -1 directory
+              // so we can return -1 directly
               return -1;
             }
             if (!(tgt.get() == src.get())) {

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/TestText.java

@@ -22,6 +22,7 @@
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.nio.charset.CharacterCodingException;
+import java.util.Arrays;
 import java.util.Random;
 import org.apache.hadoop.thirdparty.com.google.common.base.Charsets;
 import org.apache.hadoop.thirdparty.com.google.common.primitives.Bytes;
@@ -241,6 +242,17 @@ public void testFind() throws Exception {
     assertThat(text.find("cd\u20acq")).isEqualTo(-1);
   }
 
+  @Test(timeout = 10000)
+  public void testFindWithTimeout() throws Exception {
+    byte[] bytes = new byte[1000000];
+    Arrays.fill(bytes, (byte) 97);
+    String what = new String(bytes);
+    bytes[0] = (byte) 98;
+    Text text = new Text(bytes);
+
+    assertThat(text.find(what)).isEqualTo(-1);
+  }
+
   @Test
   public void testFindAfterUpdatingContents() throws Exception {
     Text text = new Text("abcd");