HADOOP-19102. [ABFS] FooterReadBufferSize should not be greater than readBufferSize (#6617)

Contributed by  Pranav Saxena

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/functional/FutureIO.java

@@ -21,6 +21,10 @@
 import java.io.IOException;
 import java.io.InterruptedIOException;
 import java.io.UncheckedIOException;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionException;
@@ -34,6 +38,9 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSBuilder;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * Future IO Helper methods.
  * <p>
@@ -55,6 +62,7 @@
 @InterfaceStability.Unstable
 public final class FutureIO {
 
+  private static final Logger LOG = LoggerFactory.getLogger(FutureIO.class.getName());
   private FutureIO() {
   }
 
@@ -114,6 +122,77 @@ public static <T> T awaitFuture(final Future<T> future,
     }
   }
 
+  /**
+   * Evaluates a collection of futures and returns their results as a list.
+   * <p>
+   * This method blocks until all futures in the collection have completed.
+   * If any future throws an exception during its execution, this method
+   * extracts and rethrows that exception.
+   * </p>
+   *
+   * @param collection collection of futures to be evaluated
+   * @param <T> type of the result.
+   * @return the list of future's result, if all went well.
+   * @throws InterruptedIOException future was interrupted
+   * @throws IOException if something went wrong
+   * @throws RuntimeException any nested RTE thrown
+   */
+  public static <T> List<T> awaitAllFutures(final Collection<Future<T>> collection)
+      throws InterruptedIOException, IOException, RuntimeException {
+    List<T> results = new ArrayList<>();
+    try {
+      for (Future<T> future : collection) {
+        results.add(future.get());
+      }
+      return results;
+    } catch (InterruptedException e) {
+      LOG.debug("Execution of future interrupted ", e);
+      throw (InterruptedIOException) new InterruptedIOException(e.toString())
+          .initCause(e);
+    } catch (ExecutionException e) {
+      LOG.debug("Execution of future failed with exception", e.getCause());
+      return raiseInnerCause(e);
+    }
+  }
+
+  /**
+   * Evaluates a collection of futures and returns their results as a list,
+   * but only waits up to the specified timeout for each future to complete.
+   * <p>
+   * This method blocks until all futures in the collection have completed or
+   * the timeout expires, whichever happens first. If any future throws an
+   * exception during its execution, this method extracts and rethrows that exception.
+   * </p>
+   *
+   * @param collection collection of futures to be evaluated
+   * @param duration timeout duration
+   * @param <T> type of the result.
+   * @return the list of future's result, if all went well.
+   * @throws InterruptedIOException future was interrupted
+   * @throws IOException if something went wrong
+   * @throws RuntimeException any nested RTE thrown
+   * @throws TimeoutException the future timed out.
+   */
+  public static <T> List<T> awaitAllFutures(final Collection<Future<T>> collection,
+      final Duration duration)
+      throws InterruptedIOException, IOException, RuntimeException,
+      TimeoutException {
+    List<T> results = new ArrayList<>();
+    try {
+      for (Future<T> future : collection) {
+        results.add(future.get(duration.toMillis(), TimeUnit.MILLISECONDS));
+      }
+      return results;
+    } catch (InterruptedException e) {
+      LOG.debug("Execution of future interrupted ", e);
+      throw (InterruptedIOException) new InterruptedIOException(e.toString())
+          .initCause(e);
+    } catch (ExecutionException e) {
+      LOG.debug("Execution of future failed with exception", e.getCause());
+      return raiseInnerCause(e);
+    }
+  }
+
   /**
    * From the inner cause of an execution exception, extract the inner cause
    * if it is an IOE or RTE.

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AbfsConfiguration.java

@@ -1230,11 +1230,6 @@ public void setOptimizeFooterRead(boolean optimizeFooterRead) {
     this.optimizeFooterRead = optimizeFooterRead;
   }
 
-  @VisibleForTesting
-  public void setFooterReadBufferSize(int footerReadBufferSize) {
-    this.footerReadBufferSize = footerReadBufferSize;
-  }
-
   @VisibleForTesting
   public void setEnableAbfsListIterator(boolean enableAbfsListIterator) {
     this.enableAbfsListIterator = enableAbfsListIterator;

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java

@@ -279,7 +279,7 @@ private FSDataInputStream open(final Path path,
     try {
       TracingContext tracingContext = new TracingContext(clientCorrelationId,
           fileSystemId, FSOperationType.OPEN, tracingHeaderFormat, listener);
-      InputStream inputStream = abfsStore
+      InputStream inputStream = getAbfsStore()
           .openFileForRead(qualifiedPath, parameters, statistics, tracingContext);
       return new FSDataInputStream(inputStream);
     } catch (AzureBlobFileSystemException ex) {

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystemStore.java

@@ -898,21 +898,21 @@ private AbfsInputStreamContext populateAbfsInputStreamContext(
         .map(c -> c.getBoolean(FS_AZURE_BUFFERED_PREAD_DISABLE, false))
         .orElse(false);
     int footerReadBufferSize = options.map(c -> c.getInt(
-        AZURE_FOOTER_READ_BUFFER_SIZE, abfsConfiguration.getFooterReadBufferSize()))
+        AZURE_FOOTER_READ_BUFFER_SIZE, getAbfsConfiguration().getFooterReadBufferSize()))
-        .orElse(abfsConfiguration.getFooterReadBufferSize());
+        .orElse(getAbfsConfiguration().getFooterReadBufferSize());
-    return new AbfsInputStreamContext(abfsConfiguration.getSasTokenRenewPeriodForStreamsInSeconds())
+    return new AbfsInputStreamContext(getAbfsConfiguration().getSasTokenRenewPeriodForStreamsInSeconds())
-            .withReadBufferSize(abfsConfiguration.getReadBufferSize())
+            .withReadBufferSize(getAbfsConfiguration().getReadBufferSize())
-            .withReadAheadQueueDepth(abfsConfiguration.getReadAheadQueueDepth())
+            .withReadAheadQueueDepth(getAbfsConfiguration().getReadAheadQueueDepth())
-            .withTolerateOobAppends(abfsConfiguration.getTolerateOobAppends())
+            .withTolerateOobAppends(getAbfsConfiguration().getTolerateOobAppends())
-            .isReadAheadEnabled(abfsConfiguration.isReadAheadEnabled())
+            .isReadAheadEnabled(getAbfsConfiguration().isReadAheadEnabled())
-            .withReadSmallFilesCompletely(abfsConfiguration.readSmallFilesCompletely())
+            .withReadSmallFilesCompletely(getAbfsConfiguration().readSmallFilesCompletely())
-            .withOptimizeFooterRead(abfsConfiguration.optimizeFooterRead())
+            .withOptimizeFooterRead(getAbfsConfiguration().optimizeFooterRead())
             .withFooterReadBufferSize(footerReadBufferSize)
-            .withReadAheadRange(abfsConfiguration.getReadAheadRange())
+            .withReadAheadRange(getAbfsConfiguration().getReadAheadRange())
             .withStreamStatistics(new AbfsInputStreamStatisticsImpl())
             .withShouldReadBufferSizeAlways(
-                abfsConfiguration.shouldReadBufferSizeAlways())
+                getAbfsConfiguration().shouldReadBufferSizeAlways())
-            .withReadAheadBlockSize(abfsConfiguration.getReadAheadBlockSize())
+            .withReadAheadBlockSize(getAbfsConfiguration().getReadAheadBlockSize())
             .withBufferedPreadDisabled(bufferedPreadDisabled)
             .withEncryptionAdapter(contextEncryptionAdapter)
             .withAbfsBackRef(fsBackRef)

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStream.java

@@ -141,7 +141,10 @@ public AbfsInputStream(
     this.path = path;
     this.contentLength = contentLength;
     this.bufferSize = abfsInputStreamContext.getReadBufferSize();
-    this.footerReadSize = abfsInputStreamContext.getFooterReadBufferSize();
+    /*
+    * FooterReadSize should not be more than bufferSize.
+    */
+    this.footerReadSize = Math.min(bufferSize, abfsInputStreamContext.getFooterReadBufferSize());
     this.readAheadQueueDepth = abfsInputStreamContext.getReadAheadQueueDepth();
     this.tolerateOobAppends = abfsInputStreamContext.isTolerateOobAppends();
     this.eTag = eTag;

hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/AbstractAbfsIntegrationTest.java

@@ -89,7 +89,7 @@ public abstract class AbstractAbfsIntegrationTest extends
   private AuthType authType;
   private boolean useConfiguredFileSystem = false;
   private boolean usingFilesystemForSASTests = false;
-  private static final int SHORTENED_GUID_LEN = 12;
+  public static final int SHORTENED_GUID_LEN = 12;
 
   protected AbstractAbfsIntegrationTest() throws Exception {
     fileSystemName = TEST_CONTAINER_PREFIX + UUID.randomUUID().toString();
@@ -366,6 +366,14 @@ public AbfsConfiguration getConfiguration() {
     return abfsConfig;
   }
 
+  public AbfsConfiguration getConfiguration(AzureBlobFileSystem fs) {
+    return fs.getAbfsStore().getAbfsConfiguration();
+  }
+
+  public Map<String, Long> getInstrumentationMap(AzureBlobFileSystem fs) {
+    return fs.getInstrumentationMap();
+  }
+
   public Configuration getRawConfiguration() {
     return abfsConfig.getRawConfiguration();
   }

hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStreamTestUtils.java

@@ -0,0 +1,295 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.fs.azurebfs.services;
+
+import java.io.IOException;
+import java.util.Random;
+import java.util.UUID;
+
+import org.assertj.core.api.Assertions;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.azurebfs.AbfsConfiguration;
+import org.apache.hadoop.fs.azurebfs.AbstractAbfsIntegrationTest;
+import org.apache.hadoop.fs.azurebfs.AzureBlobFileSystem;
+import org.apache.hadoop.fs.azurebfs.utils.UriUtils;
+
+import static org.apache.hadoop.fs.azurebfs.AbstractAbfsIntegrationTest.SHORTENED_GUID_LEN;
+import static org.apache.hadoop.fs.azurebfs.constants.ConfigurationKeys.AZURE_READ_OPTIMIZE_FOOTER_READ;
+import static org.apache.hadoop.fs.azurebfs.constants.ConfigurationKeys.AZURE_READ_SMALL_FILES_COMPLETELY;
+
+public class AbfsInputStreamTestUtils {
+
+  public static final int HUNDRED = 100;
+
+  private final AbstractAbfsIntegrationTest abstractAbfsIntegrationTest;
+
+  public AbfsInputStreamTestUtils(AbstractAbfsIntegrationTest abstractAbfsIntegrationTest) {
+    this.abstractAbfsIntegrationTest = abstractAbfsIntegrationTest;
+  }
+
+  private Path path(String filepath) throws IOException {
+    return abstractAbfsIntegrationTest.getFileSystem().makeQualified(
+        new Path(getTestPath(), getUniquePath(filepath)));
+  }
+
+  private Path getTestPath() {
+    Path path = new Path(UriUtils.generateUniqueTestPath());
+    return path;
+  }
+
+  /**
+   * Generate a unique path using the given filepath.
+   * @param filepath path string
+   * @return unique path created from filepath and a GUID
+   */
+  private Path getUniquePath(String filepath) {
+    if (filepath.equals("/")) {
+      return new Path(filepath);
+    }
+    return new Path(filepath + StringUtils
+        .right(UUID.randomUUID().toString(), SHORTENED_GUID_LEN));
+  }
+
+  /**
+   * Returns AzureBlobFileSystem instance with the required
+   * readFullFileOptimization configuration.
+   *
+   * @param readSmallFilesCompletely whether to read small files completely
+   * @return AzureBlobFileSystem instance
+   * @throws IOException exception in creating fileSystem
+   */
+  public AzureBlobFileSystem getFileSystem(boolean readSmallFilesCompletely)
+      throws IOException {
+    Configuration configuration = new Configuration(
+        abstractAbfsIntegrationTest.getRawConfiguration());
+    configuration.setBoolean(AZURE_READ_SMALL_FILES_COMPLETELY,
+        readSmallFilesCompletely);
+    configuration.setBoolean(AZURE_READ_OPTIMIZE_FOOTER_READ, false);
+    return (AzureBlobFileSystem) FileSystem.newInstance(configuration);
+  }
+
+  /**
+   * Return array of random bytes of the given length.
+   *
+   * @param length length of the byte array
+   * @return byte array
+   */
+  public byte[] getRandomBytesArray(int length) {
+    final byte[] b = new byte[length];
+    new Random().nextBytes(b);
+    return b;
+  }
+
+  /**
+   * Create a file on the file system with the given file name and content.
+   *
+   * @param fs fileSystem that stores the file
+   * @param fileName name of the file
+   * @param fileContent content of the file
+   *
+   * @return path of the file created
+   * @throws IOException exception in writing file on fileSystem
+   */
+  public Path createFileWithContent(FileSystem fs, String fileName,
+      byte[] fileContent) throws IOException {
+    Path testFilePath = path(fileName);
+    try (FSDataOutputStream oStream = fs.create(testFilePath)) {
+      oStream.write(fileContent);
+      oStream.flush();
+    }
+    return testFilePath;
+  }
+
+  /**
+   * Assert that the content read from the subsection of a file is correct.
+   *
+   * @param actualFileContent actual content of the file
+   * @param from start index of the content read
+   * @param len length of the content read
+   * @param contentRead content read from the file
+   * @param testFilePath path of the file
+   */
+  public void assertContentReadCorrectly(byte[] actualFileContent, int from,
+      int len, byte[] contentRead, Path testFilePath) {
+    Assertions.assertThat(actualFileContent.length)
+        .describedAs("From + len should be less than or equal to "
+            + "the actual file content length")
+        .isGreaterThanOrEqualTo(from + len);
+    Assertions.assertThat(contentRead.length)
+        .describedAs("Content read length should be greater than or "
+            + "equal to the len")
+        .isGreaterThanOrEqualTo(len);
+    for (int i = 0; i < len; i++) {
+      Assertions.assertThat(contentRead[i])
+          .describedAs(
+              "The test file path is " + testFilePath + ". Equality failed"
+                  + "at index " + i
+                  + " of the contentRead array. ActualFileContent is being compared from index "
+                  + from)
+          .isEqualTo(actualFileContent[i + from]);
+    }
+  }
+
+  /**
+   * Assert that the readBuffer in AbfsInputStream contain the correct starting
+   * subsequence of the file content.
+   *
+   * @param actualContent actual content of the file
+   * @param abfsInputStream abfsInputStream whose buffer to be asserted
+   * @param conf configuration
+   * @param testFilePath path of the file
+   */
+  public void assertAbfsInputStreamBufferEqualToContentStartSubsequence(byte[] actualContent,
+      AbfsInputStream abfsInputStream,
+      AbfsConfiguration conf,
+      Path testFilePath) {
+    Assertions.assertThat(abfsInputStream.getBuffer().length)
+        .describedAs("ReadBuffer should be lesser than or equal to "
+            + "readBufferSize")
+        .isLessThanOrEqualTo(conf.getReadBufferSize());
+    assertAbfsInputStreamBufferEqualityWithContentStartingSubSequence(
+        actualContent, abfsInputStream.getBuffer(), conf,
+        false, testFilePath);
+  }
+
+  /**
+   * Assert that the readBuffer in AbfsInputStream contain the incorrect starting
+   * subsequence of the file content.
+   *
+   * @param actualContent actual content of the file
+   * @param abfsInputStream abfsInputStream whose buffer to be asserted
+   * @param conf configuration
+   * @param testFilePath path of the file
+   */
+  public void assertAbfsInputStreamBufferNotEqualToContentStartSubsequence(byte[] actualContent,
+      AbfsInputStream abfsInputStream,
+      AbfsConfiguration conf,
+      Path testFilePath) {
+    Assertions.assertThat(abfsInputStream.getBuffer().length)
+        .describedAs("ReadBuffer should be lesser than or equal to "
+            + "readBufferSize")
+        .isLessThanOrEqualTo(conf.getReadBufferSize());
+    assertAbfsInputStreamBufferEqualityWithContentStartingSubSequence(
+        actualContent, abfsInputStream.getBuffer(), conf, true,
+        testFilePath);
+  }
+
+  /**
+   * Assert the equality or inequality of abfsInputStreamReadBuffer with the
+   * starting subsequence of the fileContent.
+   *
+   * @param actualContent actual content of the file
+   * @param abfsInputStreamReadBuffer buffer read from the abfsInputStream
+   * @param conf configuration
+   * @param assertEqual whether to assert equality or inequality
+   * @param testFilePath path of the file
+   */
+  private void assertAbfsInputStreamBufferEqualityWithContentStartingSubSequence(
+      byte[] actualContent,
+      byte[] abfsInputStreamReadBuffer,
+      AbfsConfiguration conf,
+      boolean assertEqual,
+      Path testFilePath) {
+    int bufferSize = conf.getReadBufferSize();
+    int actualContentSize = actualContent.length;
+    int n = Math.min(actualContentSize, bufferSize);
+    int matches = 0;
+    for (int i = 0; i < n && i < abfsInputStreamReadBuffer.length; i++) {
+      if (actualContent[i] == abfsInputStreamReadBuffer[i]) {
+        matches++;
+      }
+    }
+    if (assertEqual) {
+      Assertions.assertThat(matches).describedAs(
+          "The test file path is " + testFilePath).isEqualTo(n);
+    } else {
+      Assertions.assertThat(matches).describedAs(
+          "The test file path is " + testFilePath).isNotEqualTo(n);
+    }
+  }
+
+  /**
+   * Seek inputStream to the given seekPos.
+   *
+   * @param iStream inputStream to seek
+   * @param seekPos position to seek
+   * @throws IOException exception in seeking inputStream
+   */
+  public void seek(FSDataInputStream iStream, long seekPos)
+      throws IOException {
+    AbfsInputStream abfsInputStream
+        = (AbfsInputStream) iStream.getWrappedStream();
+    verifyAbfsInputStreamBaseStateBeforeSeek(abfsInputStream);
+    iStream.seek(seekPos);
+    verifyAbsInputStreamStateAfterSeek(abfsInputStream, seekPos);
+  }
+
+  /**
+   * Verifies that the pointers in AbfsInputStream state are unchanged and are
+   * equal to that of a newly created inputStream.
+   *
+   * @param abfsInputStream inputStream to verify
+   */
+  public void verifyAbfsInputStreamBaseStateBeforeSeek(AbfsInputStream abfsInputStream) {
+    Assertions.assertThat(abfsInputStream.getFCursor())
+        .describedAs("FCursor should be 0 at the inputStream open")
+        .isEqualTo(0);
+    Assertions.assertThat(abfsInputStream.getFCursorAfterLastRead())
+        .describedAs(
+            "FCursorAfterLastRead should be -1 at the inputStream open")
+        .isEqualTo(-1);
+    Assertions.assertThat(abfsInputStream.getLimit())
+        .describedAs("Limit should be 0 at the inputStream open")
+        .isEqualTo(0);
+    Assertions.assertThat(abfsInputStream.getBCursor())
+        .describedAs("BCursor should be 0 at the inputStream open")
+        .isEqualTo(0);
+  }
+
+  /**
+   * Verifies that only the FCursor is updated after seek and all other pointers
+   * are in their initial state.
+   *
+   * @param abfsInputStream inputStream to verify
+   * @param seekPos position to seek
+   *
+   * @throws IOException exception in inputStream operations
+   */
+  public void verifyAbsInputStreamStateAfterSeek(AbfsInputStream abfsInputStream,
+      long seekPos) throws IOException {
+    Assertions.assertThat(abfsInputStream.getPos())
+        .describedAs("InputStream's pos should be " + seekPos + " after seek")
+        .isEqualTo(seekPos);
+    Assertions.assertThat(abfsInputStream.getFCursorAfterLastRead())
+        .describedAs("FCursorAfterLastRead should be -1 after seek")
+        .isEqualTo(-1);
+    Assertions.assertThat(abfsInputStream.getLimit())
+        .describedAs("Limit should be 0 after seek")
+        .isEqualTo(0);
+    Assertions.assertThat(abfsInputStream.getBCursor())
+        .describedAs("BCursor should be 0 after seek")
+        .isEqualTo(0);
+  }
+}

hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/services/ITestAbfsInputStream.java

@@ -19,24 +19,20 @@
 package org.apache.hadoop.fs.azurebfs.services;
 
 import java.io.IOException;
-import java.lang.reflect.Field;
-import java.util.Map;
-import java.util.Random;
 
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.fs.azurebfs.AbfsConfiguration;
 import org.apache.hadoop.fs.azurebfs.AbstractAbfsIntegrationTest;
 import org.apache.hadoop.fs.azurebfs.AzureBlobFileSystem;
-import org.apache.hadoop.fs.azurebfs.AzureBlobFileSystemStore;
 import org.apache.hadoop.fs.azurebfs.utils.TracingContext;
 
 import org.assertj.core.api.Assertions;
 import org.junit.Test;
 
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.ONE_MB;
+import static org.apache.hadoop.fs.azurebfs.services.AbfsInputStreamTestUtils.HUNDRED;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyLong;
@@ -45,9 +41,9 @@
 
 public class ITestAbfsInputStream extends AbstractAbfsIntegrationTest {
 
-  protected static final int HUNDRED = 100;
+  private final AbfsInputStreamTestUtils abfsInputStreamTestUtils;
-
   public ITestAbfsInputStream() throws Exception {
+    this.abfsInputStreamTestUtils = new AbfsInputStreamTestUtils(this);
   }
 
   @Test
@@ -56,8 +52,8 @@ public void testWithNoOptimization() throws Exception {
       int fileSize = i * ONE_MB;
       final AzureBlobFileSystem fs = getFileSystem(false, false, fileSize);
       String fileName = methodName.getMethodName() + i;
-      byte[] fileContent = getRandomBytesArray(fileSize);
+      byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-      Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+      Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(fs, fileName, fileContent);
       testWithNoOptimization(fs, testFilePath, HUNDRED, fileContent);
     }
   }
@@ -71,7 +67,7 @@ protected void testWithNoOptimization(final FileSystem fs,
           .getWrappedStream();
 
       iStream = new FSDataInputStream(abfsInputStream);
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
       long totalBytesRead = 0;
       int length = HUNDRED * HUNDRED;
       do {
@@ -82,7 +78,7 @@ protected void testWithNoOptimization(final FileSystem fs,
           length = (fileContent.length - seekPos) % length;
         }
         assertEquals(length, bytesRead);
-        assertContentReadCorrectly(fileContent,
+        abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent,
             (int) (seekPos + totalBytesRead - length), length, buffer, testFilePath);
 
         assertTrue(abfsInputStream.getFCursor() >= seekPos + totalBytesRead);
@@ -101,8 +97,8 @@ public void testExceptionInOptimization() throws Exception {
       int fileSize = i * ONE_MB;
       final AzureBlobFileSystem fs = getFileSystem(true, true, fileSize);
       String fileName = methodName.getMethodName() + i;
-      byte[] fileContent = getRandomBytesArray(fileSize);
+      byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-      Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+      Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(fs, fileName, fileContent);
       testExceptionInOptimization(fs, testFilePath, fileSize - HUNDRED,
           fileSize / 4, fileContent);
     }
@@ -144,8 +140,8 @@ private void testExceptionInOptimization(final FileSystem fs,
               any(TracingContext.class));
 
       iStream = new FSDataInputStream(abfsInputStream);
-      verifyBeforeSeek(abfsInputStream);
+      abfsInputStreamTestUtils.verifyAbfsInputStreamBaseStateBeforeSeek(abfsInputStream);
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
       byte[] buffer = new byte[length];
       int bytesRead = iStream.read(buffer, 0, length);
       long actualLength = length;
@@ -154,7 +150,8 @@ private void testExceptionInOptimization(final FileSystem fs,
         actualLength = length - delta;
       }
       assertEquals(bytesRead, actualLength);
-      assertContentReadCorrectly(fileContent, seekPos, (int) actualLength, buffer, testFilePath);
+      abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent, seekPos,
+          (int) actualLength, buffer, testFilePath);
       assertEquals(fileContent.length, abfsInputStream.getFCursor());
       assertEquals(fileContent.length, abfsInputStream.getFCursorAfterLastRead());
       assertEquals(actualLength, abfsInputStream.getBCursor());
@@ -164,18 +161,6 @@ private void testExceptionInOptimization(final FileSystem fs,
     }
   }
 
-  protected AzureBlobFileSystem getFileSystem(boolean readSmallFilesCompletely)
-      throws IOException {
-    final AzureBlobFileSystem fs = getFileSystem();
-    getAbfsStore(fs).getAbfsConfiguration()
-        .setReadSmallFilesCompletely(readSmallFilesCompletely);
-    getAbfsStore(fs).getAbfsConfiguration()
-        .setOptimizeFooterRead(false);
-    getAbfsStore(fs).getAbfsConfiguration()
-        .setIsChecksumValidationEnabled(true);
-    return fs;
-  }
-
   private AzureBlobFileSystem getFileSystem(boolean optimizeFooterRead,
       boolean readSmallFileCompletely, int fileSize) throws IOException {
     final AzureBlobFileSystem fs = getFileSystem();
@@ -190,96 +175,4 @@ private AzureBlobFileSystem getFileSystem(boolean optimizeFooterRead,
     }
     return fs;
   }
-
-  protected byte[] getRandomBytesArray(int length) {
-    final byte[] b = new byte[length];
-    new Random().nextBytes(b);
-    return b;
-  }
-
-  protected Path createFileWithContent(FileSystem fs, String fileName,
-      byte[] fileContent) throws IOException {
-    Path testFilePath = path(fileName);
-    try (FSDataOutputStream oStream = fs.create(testFilePath)) {
-      oStream.write(fileContent);
-      oStream.flush();
-    }
-    return testFilePath;
-  }
-
-  protected AzureBlobFileSystemStore getAbfsStore(FileSystem fs)
-      throws NoSuchFieldException, IllegalAccessException {
-    AzureBlobFileSystem abfs = (AzureBlobFileSystem) fs;
-    Field abfsStoreField = AzureBlobFileSystem.class
-        .getDeclaredField("abfsStore");
-    abfsStoreField.setAccessible(true);
-    return (AzureBlobFileSystemStore) abfsStoreField.get(abfs);
-  }
-
-  protected Map<String, Long> getInstrumentationMap(FileSystem fs)
-      throws NoSuchFieldException, IllegalAccessException {
-    AzureBlobFileSystem abfs = (AzureBlobFileSystem) fs;
-    Field abfsCountersField = AzureBlobFileSystem.class
-        .getDeclaredField("abfsCounters");
-    abfsCountersField.setAccessible(true);
-    AbfsCounters abfsCounters = (AbfsCounters) abfsCountersField.get(abfs);
-    return abfsCounters.toMap();
-  }
-
-  protected void assertContentReadCorrectly(byte[] actualFileContent, int from,
-      int len, byte[] contentRead, Path testFilePath) {
-    for (int i = 0; i < len; i++) {
-      assertEquals("The test file path is " + testFilePath, contentRead[i], actualFileContent[i + from]);
-    }
-  }
-
-  protected void assertBuffersAreNotEqual(byte[] actualContent,
-      byte[] contentRead, AbfsConfiguration conf, Path testFilePath) {
-    assertBufferEquality(actualContent, contentRead, conf, false, testFilePath);
-  }
-
-  protected void assertBuffersAreEqual(byte[] actualContent, byte[] contentRead,
-      AbfsConfiguration conf, Path testFilePath) {
-    assertBufferEquality(actualContent, contentRead, conf, true, testFilePath);
-  }
-
-  private void assertBufferEquality(byte[] actualContent, byte[] contentRead,
-      AbfsConfiguration conf, boolean assertEqual, Path testFilePath) {
-    int bufferSize = conf.getReadBufferSize();
-    int actualContentSize = actualContent.length;
-    int n = (actualContentSize < bufferSize) ? actualContentSize : bufferSize;
-    int matches = 0;
-    for (int i = 0; i < n; i++) {
-      if (actualContent[i] == contentRead[i]) {
-        matches++;
-      }
-    }
-    if (assertEqual) {
-      assertEquals("The test file path is " + testFilePath, n, matches);
-    } else {
-      assertNotEquals("The test file path is " + testFilePath, n, matches);
-    }
-  }
-
-  protected void seek(FSDataInputStream iStream, long seekPos)
-      throws IOException {
-    AbfsInputStream abfsInputStream = (AbfsInputStream) iStream.getWrappedStream();
-    verifyBeforeSeek(abfsInputStream);
-    iStream.seek(seekPos);
-    verifyAfterSeek(abfsInputStream, seekPos);
-  }
-
-  private void verifyBeforeSeek(AbfsInputStream abfsInputStream){
-    assertEquals(0, abfsInputStream.getFCursor());
-    assertEquals(-1, abfsInputStream.getFCursorAfterLastRead());
-    assertEquals(0, abfsInputStream.getLimit());
-    assertEquals(0, abfsInputStream.getBCursor());
-  }
-
-  private void verifyAfterSeek(AbfsInputStream abfsInputStream, long seekPos) throws IOException {
-    assertEquals(seekPos, abfsInputStream.getPos());
-    assertEquals(-1, abfsInputStream.getFCursorAfterLastRead());
-    assertEquals(0, abfsInputStream.getLimit());
-    assertEquals(0, abfsInputStream.getBCursor());
-  }
 }

hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/services/ITestAbfsInputStreamReadFooter.java

@@ -19,14 +19,23 @@
 package org.apache.hadoop.fs.azurebfs.services;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FutureDataInputStreamBuilder;
+import org.apache.hadoop.fs.azurebfs.AbstractAbfsScaleTest;
 import org.apache.hadoop.fs.azurebfs.AzureBlobFileSystemStore;
 
 import org.assertj.core.api.Assertions;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FileSystem;
@@ -34,12 +43,15 @@
 import org.apache.hadoop.fs.azurebfs.AbfsConfiguration;
 import org.apache.hadoop.fs.azurebfs.AzureBlobFileSystem;
 import org.apache.hadoop.fs.azurebfs.utils.TracingContext;
+import org.apache.hadoop.util.functional.FutureIO;
 
 import static java.lang.Math.max;
 import static java.lang.Math.min;
 
 import static org.apache.hadoop.fs.azurebfs.constants.ConfigurationKeys.AZURE_FOOTER_READ_BUFFER_SIZE;
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.DEFAULT_FOOTER_READ_BUFFER_SIZE;
+import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.ONE_MB;
+import static org.apache.hadoop.fs.azurebfs.services.AbfsInputStreamTestUtils.HUNDRED;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyLong;
@@ -49,44 +61,112 @@
 import static org.apache.hadoop.fs.azurebfs.AbfsStatistic.CONNECTIONS_MADE;
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.ONE_KB;
 
-public class ITestAbfsInputStreamReadFooter extends ITestAbfsInputStream {
+public class ITestAbfsInputStreamReadFooter extends AbstractAbfsScaleTest {
 
   private static final int TEN = 10;
   private static final int TWENTY = 20;
 
+  private static ExecutorService executorService;
+
+  private static final int SIZE_256_KB = 256 * ONE_KB;
+
+  private static final Integer[] FILE_SIZES = {
+      SIZE_256_KB,
+      2 * SIZE_256_KB,
+      ONE_MB,
+      4 * ONE_MB
+  };
+
+  private static final Integer[] READ_BUFFER_SIZE = {
+      SIZE_256_KB,
+      2 * SIZE_256_KB,
+      ONE_MB,
+      4 * ONE_MB
+  };
+
+  private static final Integer[] FOOTER_READ_BUFFER_SIZE = {
+      SIZE_256_KB,
+      2 * SIZE_256_KB,
+      ONE_MB
+  };
+
+  private final AbfsInputStreamTestUtils abfsInputStreamTestUtils;
+
   public ITestAbfsInputStreamReadFooter() throws Exception {
+    this.abfsInputStreamTestUtils = new AbfsInputStreamTestUtils(this);
+  }
+
+  @BeforeClass
+  public static void init() {
+    executorService = Executors.newFixedThreadPool(
+        2 * Runtime.getRuntime().availableProcessors());
+  }
+
+  @AfterClass
+  public static void close() {
+    executorService.shutdown();
   }
 
   @Test
   public void testOnlyOneServerCallIsMadeWhenTheConfIsTrue() throws Exception {
-    testNumBackendCalls(true);
+    validateNumBackendCalls(true);
   }
 
   @Test
   public void testMultipleServerCallsAreMadeWhenTheConfIsFalse()
       throws Exception {
-    testNumBackendCalls(false);
+    validateNumBackendCalls(false);
   }
 
-  private void testNumBackendCalls(boolean optimizeFooterRead)
+
+  /**
+   * For different combination of file sizes, read buffer sizes and footer read
+   * buffer size, assert the number of server calls made when the optimization
+   * is enabled and disabled.
+   * <p>
+   * If the footer optimization is on, if the first read on the file is within the
+   * footer range (given by {@link AbfsInputStream#FOOTER_SIZE}, then the last block
+   * of size footerReadBufferSize is read from the server, and then subsequent
+   * inputStream reads from that block is returned from the buffer maintained by the
+   * AbfsInputStream. So, those reads will not result in server calls.
+   */
+  private void validateNumBackendCalls(boolean optimizeFooterRead)
       throws Exception {
     int fileIdx = 0;
-    for (int i = 0; i <= 4; i++) {
+    final List<Future<Void>> futureList = new ArrayList<>();
-      for (int j = 0; j <= 2; j++) {
+    for (int fileSize : FILE_SIZES) {
-        int fileSize = (int) Math.pow(2, i) * 256 * ONE_KB;
+      final int fileId = fileIdx++;
-        int footerReadBufferSize = (int) Math.pow(2, j) * 256 * ONE_KB;
+      Future<Void> future = executorService.submit(() -> {
-        final AzureBlobFileSystem fs = getFileSystem(
+        try (AzureBlobFileSystem spiedFs = createSpiedFs(
-            optimizeFooterRead, fileSize);
+            getRawConfiguration())) {
-        Path testFilePath = createPathAndFileWithContent(
+          Path testPath = createPathAndFileWithContent(
-            fs, fileIdx++, fileSize);
+              spiedFs, fileId, fileSize);
+          validateNumBackendCalls(spiedFs, optimizeFooterRead, fileSize,
+              testPath);
+          return null;
+        } catch (Exception ex) {
+          throw new RuntimeException(ex);
+        }
+      });
+      futureList.add(future);
+    }
+    FutureIO.awaitAllFutures(futureList);
+  }
+
+  private void validateNumBackendCalls(final AzureBlobFileSystem spiedFs,
+      final boolean optimizeFooterRead, final int fileSize, final Path testFilePath) throws Exception {
+    for (int readBufferSize : READ_BUFFER_SIZE) {
+      for (int footerReadBufferSize : FOOTER_READ_BUFFER_SIZE) {
+        changeFooterConfigs(spiedFs, optimizeFooterRead, fileSize, readBufferSize);
         int length = AbfsInputStream.FOOTER_SIZE;
         FutureDataInputStreamBuilder builder = getParameterizedBuilder(
-            testFilePath, fs, footerReadBufferSize);
+            testFilePath, spiedFs, footerReadBufferSize);
         try (FSDataInputStream iStream = builder.build().get()) {
           verifyConfigValueInStream(iStream, footerReadBufferSize);
           byte[] buffer = new byte[length];
 
-          Map<String, Long> metricMap = getInstrumentationMap(fs);
+          Map<String, Long> metricMap =
+              getInstrumentationMap(spiedFs);
           long requestsMadeBeforeTest = metricMap
               .get(CONNECTIONS_MADE.getStatName());
 
@@ -99,7 +179,7 @@ private void testNumBackendCalls(boolean optimizeFooterRead)
           iStream.seek(fileSize - (TWENTY * ONE_KB));
           iStream.read(buffer, 0, length);
 
-          metricMap = getInstrumentationMap(fs);
+          metricMap = getInstrumentationMap(spiedFs);
           long requestsMadeAfterTest = metricMap
               .get(CONNECTIONS_MADE.getStatName());
 
@@ -117,74 +197,104 @@ private void testNumBackendCalls(boolean optimizeFooterRead)
 
   @Test
   public void testSeekToBeginAndReadWithConfTrue() throws Exception {
-    testSeekAndReadWithConf(true, SeekTo.BEGIN);
+    validateSeekAndReadWithConf(true, SeekTo.BEGIN);
   }
 
   @Test
   public void testSeekToBeginAndReadWithConfFalse() throws Exception {
-    testSeekAndReadWithConf(false, SeekTo.BEGIN);
+    validateSeekAndReadWithConf(false, SeekTo.BEGIN);
   }
 
   @Test
   public void testSeekToBeforeFooterAndReadWithConfTrue() throws Exception {
-    testSeekAndReadWithConf(true, SeekTo.BEFORE_FOOTER_START);
+    validateSeekAndReadWithConf(true, SeekTo.BEFORE_FOOTER_START);
   }
 
   @Test
   public void testSeekToBeforeFooterAndReadWithConfFalse() throws Exception {
-    testSeekAndReadWithConf(false, SeekTo.BEFORE_FOOTER_START);
+    validateSeekAndReadWithConf(false, SeekTo.BEFORE_FOOTER_START);
   }
 
   @Test
   public void testSeekToFooterAndReadWithConfTrue() throws Exception {
-    testSeekAndReadWithConf(true, SeekTo.AT_FOOTER_START);
+    validateSeekAndReadWithConf(true, SeekTo.AT_FOOTER_START);
   }
 
   @Test
   public void testSeekToFooterAndReadWithConfFalse() throws Exception {
-    testSeekAndReadWithConf(false, SeekTo.AT_FOOTER_START);
+    validateSeekAndReadWithConf(false, SeekTo.AT_FOOTER_START);
   }
 
   @Test
   public void testSeekToAfterFooterAndReadWithConfTrue() throws Exception {
-    testSeekAndReadWithConf(true, SeekTo.AFTER_FOOTER_START);
+    validateSeekAndReadWithConf(true, SeekTo.AFTER_FOOTER_START);
   }
 
   @Test
   public void testSeekToToAfterFooterAndReadWithConfFalse() throws Exception {
-    testSeekAndReadWithConf(false, SeekTo.AFTER_FOOTER_START);
+    validateSeekAndReadWithConf(false, SeekTo.AFTER_FOOTER_START);
   }
 
   @Test
   public void testSeekToEndAndReadWithConfTrue() throws Exception {
-    testSeekAndReadWithConf(true, SeekTo.END);
+    validateSeekAndReadWithConf(true, SeekTo.END);
   }
 
   @Test
   public void testSeekToEndAndReadWithConfFalse() throws Exception {
-    testSeekAndReadWithConf(false, SeekTo.END);
+    validateSeekAndReadWithConf(false, SeekTo.END);
   }
 
-  private void testSeekAndReadWithConf(boolean optimizeFooterRead,
+  /**
+   * For different combination of file sizes, read buffer sizes and footer read
+   * buffer size, and read from different seek positions, validate the internal
+   * state of AbfsInputStream.
+   */
+  private void validateSeekAndReadWithConf(boolean optimizeFooterRead,
       SeekTo seekTo) throws Exception {
+    int fileIdx = 0;
+    List<Future<Void>> futureList = new ArrayList<>();
+    for (int fileSize : FILE_SIZES) {
+      final int fileId = fileIdx++;
+      futureList.add(executorService.submit(() -> {
+        try (AzureBlobFileSystem spiedFs = createSpiedFs(
+            getRawConfiguration())) {
+          String fileName = methodName.getMethodName() + fileId;
+          byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
+          Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(spiedFs, fileName,
+              fileContent);
+          for (int readBufferSize : READ_BUFFER_SIZE) {
+            validateSeekAndReadWithConf(spiedFs, optimizeFooterRead, seekTo,
+                readBufferSize, fileSize, testFilePath, fileContent);
+          }
+          return null;
+        } catch (Exception ex) {
+          throw new RuntimeException(ex);
+        }
+      }));
+    }
+    FutureIO.awaitAllFutures(futureList);
+  }
+
+  private void validateSeekAndReadWithConf(final AzureBlobFileSystem spiedFs,
+      final boolean optimizeFooterRead,
+      final SeekTo seekTo,
+      final int readBufferSize,
+      final int fileSize,
+      final Path testFilePath,
+      final byte[] fileContent)
+      throws Exception {
     // Running the test for file sizes ranging from 256 KB to 4 MB with
     // Footer Read Buffer size ranging from 256 KB to 1 MB
     // This will cover files less than footer read buffer size,
     // Files between footer read buffer and read buffer size
     // Files bigger than read buffer size
-    int fileIdx = 0;
+    for (int footerReadBufferSize : FOOTER_READ_BUFFER_SIZE) {
-    for (int i = 0; i <= 4; i++) {
+      changeFooterConfigs(spiedFs, optimizeFooterRead, fileSize,
-      for (int j = 0; j <= 2; j++) {
+          readBufferSize);
-        int fileSize = (int) Math.pow(2, i) * 256 * ONE_KB;
+
-        int footerReadBufferSize = (int) Math.pow(2, j) * 256 * ONE_KB;
+      seekReadAndTest(spiedFs, testFilePath, seekPos(seekTo, fileSize), HUNDRED,
-        final AzureBlobFileSystem fs = getFileSystem(
+          fileContent, footerReadBufferSize);
-            optimizeFooterRead, fileSize);
-        String fileName = methodName.getMethodName() + fileIdx++;
-        byte[] fileContent = getRandomBytesArray(fileSize);
-        Path testFilePath = createFileWithContent(fs, fileName, fileContent);
-        seekReadAndTest(fs, testFilePath, seekPos(seekTo, fileSize), HUNDRED,
-            fileContent, footerReadBufferSize);
-      }
     }
   }
 
@@ -216,7 +326,7 @@ private void seekReadAndTest(final AzureBlobFileSystem fs,
       AbfsInputStream abfsInputStream = (AbfsInputStream) iStream.getWrappedStream();
       verifyConfigValueInStream(iStream, footerReadBufferSize);
       long readBufferSize = abfsInputStream.getBufferSize();
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
       byte[] buffer = new byte[length];
       long bytesRead = iStream.read(buffer, 0, length);
 
@@ -260,13 +370,13 @@ private void seekReadAndTest(final AzureBlobFileSystem fs,
       assertEquals(expectedBCursor, abfsInputStream.getBCursor());
       assertEquals(actualLength, bytesRead);
       //  Verify user-content read
-      assertContentReadCorrectly(fileContent, seekPos, (int) actualLength, buffer, testFilePath);
+      abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent, seekPos, (int) actualLength, buffer, testFilePath);
       //  Verify data read to AbfsInputStream buffer
       int from = seekPos;
       if (optimizationOn) {
         from = (int) max(0, actualContentLength - footerReadBufferSize);
       }
-      assertContentReadCorrectly(fileContent, from, (int) abfsInputStream.getLimit(),
+      abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent, from, (int) abfsInputStream.getLimit(),
           abfsInputStream.getBuffer(), testFilePath);
     }
   }
@@ -274,44 +384,67 @@ private void seekReadAndTest(final AzureBlobFileSystem fs,
   @Test
   public void testPartialReadWithNoData() throws Exception {
     int fileIdx = 0;
-    for (int i = 0; i <= 4; i++) {
+    List<Future<Void>> futureList = new ArrayList<>();
-      for (int j = 0; j <= 2; j++) {
+    for (int fileSize : FILE_SIZES) {
-        int fileSize = (int) Math.pow(2, i) * 256 * ONE_KB;
+      final int fileId = fileIdx++;
-        int footerReadBufferSize = (int) Math.pow(2, j) * 256 * ONE_KB;
+      final String fileName = methodName.getMethodName() + fileId;
-        final AzureBlobFileSystem fs = getFileSystem(
+      futureList.add(executorService.submit(() -> {
-            true, fileSize, footerReadBufferSize);
+        try (AzureBlobFileSystem spiedFs = createSpiedFs(
-        String fileName = methodName.getMethodName() + fileIdx++;
+            getRawConfiguration())) {
-        byte[] fileContent = getRandomBytesArray(fileSize);
+          byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-        Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+          Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(spiedFs, fileName,
-        testPartialReadWithNoData(fs, testFilePath,
+              fileContent);
-            fileSize - AbfsInputStream.FOOTER_SIZE, AbfsInputStream.FOOTER_SIZE,
+          validatePartialReadWithNoData(spiedFs, fileSize, fileContent,
-            fileContent, footerReadBufferSize);
+              testFilePath);
+          return null;
+        } catch (Exception ex) {
+          throw new RuntimeException(ex);
+        }
+      }));
+      FutureIO.awaitAllFutures(futureList);
+    }
+  }
+
+  private void validatePartialReadWithNoData(final AzureBlobFileSystem spiedFs,
+      final int fileSize,
+      final byte[] fileContent,
+      Path testFilePath) throws IOException {
+    for (int readBufferSize : READ_BUFFER_SIZE) {
+      for (int footerReadBufferSize : FOOTER_READ_BUFFER_SIZE) {
+        changeFooterConfigs(spiedFs, true, fileSize,
+            footerReadBufferSize, readBufferSize);
+
+        validatePartialReadWithNoData(spiedFs, testFilePath,
+            fileSize - AbfsInputStream.FOOTER_SIZE,
+            AbfsInputStream.FOOTER_SIZE,
+            fileContent, footerReadBufferSize, readBufferSize);
       }
     }
   }
 
-  private void testPartialReadWithNoData(final FileSystem fs,
+  private void validatePartialReadWithNoData(final FileSystem fs,
       final Path testFilePath, final int seekPos, final int length,
-      final byte[] fileContent, int footerReadBufferSize) throws IOException {
+      final byte[] fileContent, int footerReadBufferSize, final int readBufferSize) throws IOException {
     FSDataInputStream iStream = fs.open(testFilePath);
     try {
       AbfsInputStream abfsInputStream = (AbfsInputStream) iStream
           .getWrappedStream();
+      int footerBufferSizeAssert = Math.min(readBufferSize, footerReadBufferSize);
       Assertions.assertThat(abfsInputStream.getFooterReadBufferSize())
           .describedAs("Footer Read Buffer Size Should be same as what set in builder")
-          .isEqualTo(footerReadBufferSize);
+          .isEqualTo(footerBufferSizeAssert);
       abfsInputStream = spy(abfsInputStream);
       doReturn(10).doReturn(10).doCallRealMethod().when(abfsInputStream)
           .readRemote(anyLong(), any(), anyInt(), anyInt(),
               any(TracingContext.class));
 
       iStream = new FSDataInputStream(abfsInputStream);
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
 
       byte[] buffer = new byte[length];
       int bytesRead = iStream.read(buffer, 0, length);
       assertEquals(length, bytesRead);
-      assertContentReadCorrectly(fileContent, seekPos, length, buffer, testFilePath);
+      abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent, seekPos, length, buffer, testFilePath);
       assertEquals(fileContent.length, abfsInputStream.getFCursor());
       assertEquals(length, abfsInputStream.getBCursor());
       assertTrue(abfsInputStream.getLimit() >= length);
@@ -322,28 +455,51 @@ private void testPartialReadWithNoData(final FileSystem fs,
 
   @Test
   public void testPartialReadWithSomeData() throws Exception {
-    for (int i = 0; i <= 4; i++) {
+    int fileIdx = 0;
-      for (int j = 0; j <= 2; j++) {
+    List<Future<Void>> futureList = new ArrayList<>();
-        int fileSize = (int) Math.pow(2, i) * 256 * ONE_KB;
+    for (int fileSize : FILE_SIZES) {
-        int footerReadBufferSize = (int) Math.pow(2, j) * 256 * ONE_KB;
+      final int fileId = fileIdx++;
-        final AzureBlobFileSystem fs = getFileSystem(true,
+      futureList.add(executorService.submit(() -> {
-            fileSize, footerReadBufferSize);
+        try (AzureBlobFileSystem spiedFs = createSpiedFs(
-        String fileName = methodName.getMethodName() + i;
+            getRawConfiguration())) {
-        byte[] fileContent = getRandomBytesArray(fileSize);
+          String fileName = methodName.getMethodName() + fileId;
-        Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+          byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-        testPartialReadWithSomeData(fs, testFilePath,
+          Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(spiedFs, fileName,
-            fileSize - AbfsInputStream.FOOTER_SIZE, AbfsInputStream.FOOTER_SIZE,
+              fileContent);
-            fileContent, footerReadBufferSize);
+          validatePartialReadWithSomeData(spiedFs, fileSize, testFilePath,
+              fileContent);
+          return null;
+        } catch (Exception ex) {
+          throw new RuntimeException(ex);
+        }
+      }));
+    }
+    FutureIO.awaitAllFutures(futureList);
+  }
+
+  private void validatePartialReadWithSomeData(final AzureBlobFileSystem spiedFs,
+      final int fileSize, final Path testFilePath, final byte[] fileContent)
+      throws IOException {
+    for (int readBufferSize : READ_BUFFER_SIZE) {
+      for (int footerReadBufferSize : FOOTER_READ_BUFFER_SIZE) {
+        changeFooterConfigs(spiedFs, true,
+            fileSize, footerReadBufferSize, readBufferSize);
+
+        validatePartialReadWithSomeData(spiedFs, testFilePath,
+            fileSize - AbfsInputStream.FOOTER_SIZE,
+            AbfsInputStream.FOOTER_SIZE,
+            fileContent, footerReadBufferSize, readBufferSize);
       }
     }
   }
 
-  private void testPartialReadWithSomeData(final FileSystem fs,
+  private void validatePartialReadWithSomeData(final FileSystem fs,
       final Path testFilePath, final int seekPos, final int length,
-      final byte[] fileContent, final int footerReadBufferSize) throws IOException {
+      final byte[] fileContent, final int footerReadBufferSize,
+      final int readBufferSize) throws IOException {
     FSDataInputStream iStream = fs.open(testFilePath);
     try {
-      verifyConfigValueInStream(iStream, footerReadBufferSize);
+      verifyConfigValueInStream(iStream, Math.min(footerReadBufferSize, readBufferSize));
       AbfsInputStream abfsInputStream = spy((AbfsInputStream) iStream
           .getWrappedStream());
       //  first readRemote, will return first 10 bytes
@@ -358,7 +514,7 @@ private void testPartialReadWithSomeData(final FileSystem fs,
               any(TracingContext.class));
 
       iStream = new FSDataInputStream(abfsInputStream);
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
 
       byte[] buffer = new byte[length];
       int bytesRead = iStream.read(buffer, 0, length);
@@ -379,7 +535,7 @@ private void testPartialReadWithSomeData(final FileSystem fs,
   public void testFooterReadBufferSizeConfiguration() throws Exception {
     Configuration config = new Configuration(this.getRawConfiguration());
     config.unset(AZURE_FOOTER_READ_BUFFER_SIZE);
-    try (AzureBlobFileSystem fs = (AzureBlobFileSystem) FileSystem.newInstance(config)){
+    try (AzureBlobFileSystem fs = createSpiedFs(config)){
       Path testFilePath = createPathAndFileWithContent(fs, 0, ONE_KB);
       final int footerReadBufferSizeConfig = 4 * ONE_KB;
       final int footerReadBufferSizeBuilder = 5 * ONE_KB;
@@ -389,13 +545,13 @@ public void testFooterReadBufferSizeConfiguration() throws Exception {
       verifyConfigValueInStream(iStream, DEFAULT_FOOTER_READ_BUFFER_SIZE);
 
       // Verify that value set in config is used if builder is not used
-      getAbfsStore(fs).getAbfsConfiguration()
+      AbfsConfiguration spiedConfig = fs.getAbfsStore().getAbfsConfiguration();
-          .setFooterReadBufferSize(footerReadBufferSizeConfig);
+      Mockito.doReturn(footerReadBufferSizeConfig).when(spiedConfig).getFooterReadBufferSize();
       iStream = fs.open(testFilePath);
       verifyConfigValueInStream(iStream, footerReadBufferSizeConfig);
 
       // Verify that when builder is used value set in parameters is used
-      getAbfsStore(fs).getAbfsConfiguration().unset(AZURE_FOOTER_READ_BUFFER_SIZE);
+      spiedConfig.unset(AZURE_FOOTER_READ_BUFFER_SIZE);
       FutureDataInputStreamBuilder builder = fs.openFile(testFilePath);
       builder.opt(AZURE_FOOTER_READ_BUFFER_SIZE,
           footerReadBufferSizeBuilder);
@@ -404,15 +560,13 @@ public void testFooterReadBufferSizeConfiguration() throws Exception {
 
       // Verify that when builder is used value set in parameters is used
       // even if config is set
-      getAbfsStore(fs).getAbfsConfiguration()
+      Mockito.doReturn(footerReadBufferSizeConfig).when(spiedConfig).getFooterReadBufferSize();
-          .setFooterReadBufferSize(footerReadBufferSizeConfig);
       iStream = builder.build().get();
       verifyConfigValueInStream(iStream, footerReadBufferSizeBuilder);
 
       // Verify that when the builder is used and parameter in builder is not set,
       // the value set in configuration is used
-      getAbfsStore(fs).getAbfsConfiguration()
+      Mockito.doReturn(footerReadBufferSizeConfig).when(spiedConfig).getFooterReadBufferSize();
-          .setFooterReadBufferSize(footerReadBufferSizeConfig);
       builder = fs.openFile(testFilePath);
       iStream = builder.build().get();
       verifyConfigValueInStream(iStream, footerReadBufferSizeConfig);
@@ -431,8 +585,8 @@ private void verifyConfigValueInStream(final FSDataInputStream inputStream,
   private Path createPathAndFileWithContent(final AzureBlobFileSystem fs,
       final int fileIdx, final int fileSize) throws Exception {
     String fileName = methodName.getMethodName() + fileIdx;
-    byte[] fileContent = getRandomBytesArray(fileSize);
+    byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-    return createFileWithContent(fs, fileName, fileContent);
+    return abfsInputStreamTestUtils.createFileWithContent(fs, fileName, fileContent);
   }
 
   private FutureDataInputStreamBuilder getParameterizedBuilder(final Path path,
@@ -443,27 +597,45 @@ private FutureDataInputStreamBuilder getParameterizedBuilder(final Path path,
     return builder;
   }
 
-  private AzureBlobFileSystem getFileSystem(final boolean optimizeFooterRead,
+  private void changeFooterConfigs(final AzureBlobFileSystem spiedFs,
-      final int fileSize) throws IOException {
+      final boolean optimizeFooterRead, final int fileSize,
-    final AzureBlobFileSystem fs = getFileSystem();
+      final int readBufferSize) {
-    AzureBlobFileSystemStore store = getAbfsStore(fs);
+    AbfsConfiguration configuration = spiedFs.getAbfsStore()
-    store.getAbfsConfiguration().setOptimizeFooterRead(optimizeFooterRead);
+        .getAbfsConfiguration();
-    if (fileSize <= store.getAbfsConfiguration().getReadBufferSize()) {
+    Mockito.doReturn(optimizeFooterRead)
-      store.getAbfsConfiguration().setReadSmallFilesCompletely(false);
+        .when(configuration)
+        .optimizeFooterRead();
+    if (fileSize <= readBufferSize) {
+      Mockito.doReturn(false).when(configuration).readSmallFilesCompletely();
     }
-    return fs;
   }
 
-  private AzureBlobFileSystem getFileSystem(final boolean optimizeFooterRead,
+  private AzureBlobFileSystem createSpiedFs(Configuration configuration)
-      final int fileSize, final int footerReadBufferSize) throws IOException {
+      throws IOException {
-    final AzureBlobFileSystem fs = getFileSystem();
+    AzureBlobFileSystem spiedFs = Mockito.spy(
-    AzureBlobFileSystemStore store = getAbfsStore(fs);
+        (AzureBlobFileSystem) FileSystem.newInstance(configuration));
-    store.getAbfsConfiguration().setOptimizeFooterRead(optimizeFooterRead);
+    AzureBlobFileSystemStore store = Mockito.spy(spiedFs.getAbfsStore());
-    store.getAbfsConfiguration().setFooterReadBufferSize(footerReadBufferSize);
+    Mockito.doReturn(store).when(spiedFs).getAbfsStore();
-    if (fileSize <= store.getAbfsConfiguration().getReadBufferSize()) {
+    AbfsConfiguration spiedConfig = Mockito.spy(store.getAbfsConfiguration());
-      store.getAbfsConfiguration().setReadSmallFilesCompletely(false);
+    Mockito.doReturn(spiedConfig).when(store).getAbfsConfiguration();
+    return spiedFs;
+  }
+
+  private void changeFooterConfigs(final AzureBlobFileSystem spiedFs,
+      final boolean optimizeFooterRead, final int fileSize,
+      final int footerReadBufferSize, final int readBufferSize) {
+    AbfsConfiguration configuration = spiedFs.getAbfsStore()
+        .getAbfsConfiguration();
+    Mockito.doReturn(optimizeFooterRead)
+        .when(configuration)
+        .optimizeFooterRead();
+    Mockito.doReturn(footerReadBufferSize)
+        .when(configuration)
+        .getFooterReadBufferSize();
+    Mockito.doReturn(readBufferSize).when(configuration).getReadBufferSize();
+    if (fileSize <= readBufferSize) {
+      Mockito.doReturn(false).when(configuration).readSmallFilesCompletely();
     }
-    return fs;
   }
 
   private enum SeekTo {

hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/services/ITestAbfsInputStreamSmallFileReads.java

@@ -27,6 +27,7 @@
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.azurebfs.AbstractAbfsIntegrationTest;
 import org.apache.hadoop.fs.azurebfs.AzureBlobFileSystem;
 import org.apache.hadoop.fs.azurebfs.utils.TracingContext;
 
@@ -40,9 +41,12 @@
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.ONE_KB;
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.ONE_MB;
 
-public class ITestAbfsInputStreamSmallFileReads extends ITestAbfsInputStream {
+public class ITestAbfsInputStreamSmallFileReads extends
+    AbstractAbfsIntegrationTest {
 
+  private final AbfsInputStreamTestUtils abfsInputStreamTestUtils;
   public ITestAbfsInputStreamSmallFileReads() throws Exception {
+    this.abfsInputStreamTestUtils = new AbfsInputStreamTestUtils(this);
   }
 
   @Test
@@ -58,12 +62,20 @@ public void testMultipleServerCallsAreMadeWhenTheConfIsFalse()
 
   private void testNumBackendCalls(boolean readSmallFilesCompletely)
       throws Exception {
-    final AzureBlobFileSystem fs = getFileSystem(readSmallFilesCompletely);
+    try (AzureBlobFileSystem fs = abfsInputStreamTestUtils.getFileSystem(
+        readSmallFilesCompletely)) {
+      validateNumBackendCalls(readSmallFilesCompletely, fs);
+    }
+  }
+
+  private void validateNumBackendCalls(final boolean readSmallFilesCompletely,
+      final AzureBlobFileSystem fs)
+      throws IOException, NoSuchFieldException, IllegalAccessException {
     for (int i = 1; i <= 4; i++) {
       String fileName = methodName.getMethodName() + i;
       int fileSize = i * ONE_MB;
-      byte[] fileContent = getRandomBytesArray(fileSize);
+      byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-      Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+      Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(fs, fileName, fileContent);
       int length = ONE_KB;
       try (FSDataInputStream iStream = fs.open(testFilePath)) {
         byte[] buffer = new byte[length];
@@ -158,12 +170,23 @@ public void testSeekToMiddleAndReadBigFileWithConfFalse() throws Exception {
 
   private void testSeekAndReadWithConf(SeekTo seekTo, int startFileSizeInMB,
       int endFileSizeInMB, boolean readSmallFilesCompletely) throws Exception {
-    final AzureBlobFileSystem fs = getFileSystem(readSmallFilesCompletely);
+    try (AzureBlobFileSystem fs = abfsInputStreamTestUtils.getFileSystem(
+        readSmallFilesCompletely)) {
+      validateSeekAndReadWithConf(seekTo, startFileSizeInMB, endFileSizeInMB,
+          fs);
+    }
+  }
+
+  private void validateSeekAndReadWithConf(final SeekTo seekTo,
+      final int startFileSizeInMB,
+      final int endFileSizeInMB,
+      final AzureBlobFileSystem fs)
+      throws IOException, NoSuchFieldException, IllegalAccessException {
     for (int i = startFileSizeInMB; i <= endFileSizeInMB; i++) {
       String fileName = methodName.getMethodName() + i;
       int fileSize = i * ONE_MB;
-      byte[] fileContent = getRandomBytesArray(fileSize);
+      byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(fileSize);
-      Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+      Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(fs, fileName, fileContent);
       int length = ONE_KB;
       int seekPos = seekPos(seekTo, fileSize, length);
       seekReadAndTest(fs, testFilePath, seekPos, length, fileContent);
@@ -183,13 +206,13 @@ private int seekPos(SeekTo seekTo, int fileSize, int length) {
   private void seekReadAndTest(FileSystem fs, Path testFilePath, int seekPos,
       int length, byte[] fileContent)
       throws IOException, NoSuchFieldException, IllegalAccessException {
-    AbfsConfiguration conf = getAbfsStore(fs).getAbfsConfiguration();
+    AbfsConfiguration conf = getConfiguration((AzureBlobFileSystem) fs);
     try (FSDataInputStream iStream = fs.open(testFilePath)) {
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
       byte[] buffer = new byte[length];
       int bytesRead = iStream.read(buffer, 0, length);
       assertEquals(bytesRead, length);
-      assertContentReadCorrectly(fileContent, seekPos, length, buffer, testFilePath);
+      abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent, seekPos, length, buffer, testFilePath);
       AbfsInputStream abfsInputStream = (AbfsInputStream) iStream
           .getWrappedStream();
 
@@ -199,15 +222,15 @@ private void seekReadAndTest(FileSystem fs, Path testFilePath, int seekPos,
       int expectedLimit, expectedFCursor;
       int expectedBCursor;
       if (conf.readSmallFilesCompletely() && smallFile) {
-        assertBuffersAreEqual(fileContent, abfsInputStream.getBuffer(), conf, testFilePath);
+        abfsInputStreamTestUtils.assertAbfsInputStreamBufferNotEqualToContentStartSubsequence(fileContent, abfsInputStream, conf, testFilePath);
         expectedFCursor = fileContentLength;
         expectedLimit = fileContentLength;
         expectedBCursor = seekPos + length;
       } else {
         if ((seekPos == 0)) {
-          assertBuffersAreEqual(fileContent, abfsInputStream.getBuffer(), conf, testFilePath);
+          abfsInputStreamTestUtils.assertAbfsInputStreamBufferNotEqualToContentStartSubsequence(fileContent, abfsInputStream, conf, testFilePath);
         } else {
-          assertBuffersAreNotEqual(fileContent, abfsInputStream.getBuffer(),
+          abfsInputStreamTestUtils.assertAbfsInputStreamBufferEqualToContentStartSubsequence(fileContent, abfsInputStream,
               conf, testFilePath);
         }
         expectedBCursor = length;
@@ -229,12 +252,16 @@ private void seekReadAndTest(FileSystem fs, Path testFilePath, int seekPos,
   public void testPartialReadWithNoData() throws Exception {
     for (int i = 2; i <= 4; i++) {
       int fileSize = i * ONE_MB;
-      final AzureBlobFileSystem fs = getFileSystem(true);
+      try (AzureBlobFileSystem fs = abfsInputStreamTestUtils.getFileSystem(
-      String fileName = methodName.getMethodName() + i;
+          true)) {
-      byte[] fileContent = getRandomBytesArray(fileSize);
+        String fileName = methodName.getMethodName() + i;
-      Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+        byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(
-      partialReadWithNoData(fs, testFilePath, fileSize / 2, fileSize / 4,
+            fileSize);
-          fileContent);
+        Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(fs,
+            fileName, fileContent);
+        partialReadWithNoData(fs, testFilePath, fileSize / 2, fileSize / 4,
+            fileContent);
+      }
     }
   }
 
@@ -256,11 +283,11 @@ private void partialReadWithNoData(final FileSystem fs,
               any(TracingContext.class));
 
       iStream = new FSDataInputStream(abfsInputStream);
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
       byte[] buffer = new byte[length];
       int bytesRead = iStream.read(buffer, 0, length);
       assertEquals(bytesRead, length);
-      assertContentReadCorrectly(fileContent, seekPos, length, buffer, testFilePath);
+      abfsInputStreamTestUtils.assertContentReadCorrectly(fileContent, seekPos, length, buffer, testFilePath);
       assertEquals(fileContent.length, abfsInputStream.getFCursor());
       assertEquals(fileContent.length,
           abfsInputStream.getFCursorAfterLastRead());
@@ -275,12 +302,16 @@ private void partialReadWithNoData(final FileSystem fs,
   public void testPartialReadWithSomeData() throws Exception {
     for (int i = 2; i <= 4; i++) {
       int fileSize = i * ONE_MB;
-      final AzureBlobFileSystem fs = getFileSystem(true);
+      try (AzureBlobFileSystem fs = abfsInputStreamTestUtils.getFileSystem(
-      String fileName = methodName.getMethodName() + i;
+          true)) {
-      byte[] fileContent = getRandomBytesArray(fileSize);
+        String fileName = methodName.getMethodName() + i;
-      Path testFilePath = createFileWithContent(fs, fileName, fileContent);
+        byte[] fileContent = abfsInputStreamTestUtils.getRandomBytesArray(
-      partialReadWithSomeData(fs, testFilePath, fileSize / 2,
+            fileSize);
-          fileSize / 4, fileContent);
+        Path testFilePath = abfsInputStreamTestUtils.createFileWithContent(fs,
+            fileName, fileContent);
+        partialReadWithSomeData(fs, testFilePath, fileSize / 2,
+            fileSize / 4, fileContent);
+      }
     }
   }
 
@@ -307,7 +338,7 @@ private void partialReadWithSomeData(final FileSystem fs,
               any(TracingContext.class));
 
       iStream = new FSDataInputStream(abfsInputStream);
-      seek(iStream, seekPos);
+      abfsInputStreamTestUtils.seek(iStream, seekPos);
 
       byte[] buffer = new byte[length];
       int bytesRead = iStream.read(buffer, 0, length);