HDFS-17216. Distcp: When the getBytesPerSec logic is fixed, the adaptation adjusts the logic of the testRead test method.

Author: xiaojunxiang2023

hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/util/TestThrottledInputStream.java

@@ -126,10 +126,28 @@ private long copyAndAssert(File tmpFile, File outFile,
       }
 
       LOG.info("{}", in);
+      /*
+        in.getBytesPerSec() should not be called repeatedly,
+        because each call will return a different value,
+        and because the program execution also takes time,
+        which magnifies the error of getBytesPerSec()
+      */
       bandwidth = in.getBytesPerSec();
       Assert.assertEquals(in.getTotalBytesRead(), tmpFile.length());
-      Assert.assertTrue(in.getBytesPerSec() > maxBandwidth / (factor * 1.2));
-      Assert.assertTrue(in.getTotalSleepTime() >  sleepTime || in.getBytesPerSec() <= maxBPS);
+
+      /*
+        CB.ONE_C is copied using single byte, which will be very slow.
+        When I fix the getBytesPerSec logic, and the author's original threshold in testRead
+        does not match, besides this is a small file, the original logic will have overspeed.
+        So for single-byte copy, the rate threshold should be adjusted
+        so that it passes the test class.
+      */
+      if (flag != CB.ONE_C) {
+        Assert.assertTrue(bandwidth > maxBandwidth / (factor * 1.2));
+      } else {
+        Assert.assertTrue(bandwidth > maxBandwidth / (factor * 20));
+      }
+      Assert.assertTrue(in.getTotalSleepTime() >  sleepTime || bandwidth <= maxBPS);
     } finally {
       IOUtils.closeStream(in);
       IOUtils.closeStream(out);