test

Author: ChrisHegarty

lucene/misc/src/test/org/apache/lucene/misc/store/TestDirectIODirectory.java

@@ -209,4 +209,31 @@ public void testUseDirectIODefaults() throws Exception {
               OptionalLong.of(largeSize)));
     }
   }
+
+  // Ping-pong seeks should be really fast, since the position should be within buffer.
+  // The test should complete within sub-second times, not minutes.
+  public void testSeekSmall() throws IOException {
+    Path tmpDir = createTempDir("testSeekSmall");
+    int blockSize = Math.toIntExact(Files.getFileStore(tmpDir).getBlockSize());
+    try (Directory dir = getDirectory(tmpDir)) {
+      int len = atLeast(100);
+      try (IndexOutput o = dir.createOutput("out", newIOContext(random()))) {
+        byte[] b = new byte[len];
+        for (int i = 0; i < len; i++) {
+          b[i] = (byte) i;
+        }
+        o.writeBytes(b, 0, len);
+      }
+      try (IndexInput in = dir.openInput("out", newIOContext(random()))) {
+        for (int i = 0; i < 100_000; i++) {
+          in.seek(2);
+          assertEquals(2, in.readByte());
+          in.seek(1);
+          assertEquals(1, in.readByte());
+          in.seek(0);
+          assertEquals(0, in.readByte());
+        }
+      }
+    }
+  }
 }