2 files changed, 33 insertions, 0 deletions
diff --git a/vespajlib/src/test/java/com/yahoo/compress/ZstdCompressorTest.java b/vespajlib/src/test/java/com/yahoo/compress/ZstdCompressorTest.java
index 146199dc860..f38ce4ad953 100644
--- a/vespajlib/src/test/java/com/yahoo/compress/ZstdCompressorTest.java
+++ b/vespajlib/src/test/java/com/yahoo/compress/ZstdCompressorTest.java
@@ -4,6 +4,7 @@ package com.yahoo.compress;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * @author bjorncs
@@ -19,4 +20,18 @@ class ZstdCompressorTest {
         assertArrayEquals(inputData, decompressedData);
     }
 
+    @Test
+    void compressed_size_is_less_than_uncompressed() {
+        StringBuilder builder = new StringBuilder();
+        for (int i = 0; i < 100; i++) {
+            builder.append("The quick brown fox jumps over the lazy dog").append('\n');
+        }
+        byte[] inputData = builder.toString().getBytes();
+        ZstdCompressor compressor = new ZstdCompressor();
+        byte[] compressedData = compressor.compress(inputData, 0, inputData.length);
+        assertTrue(
+                compressedData.length < inputData.length,
+                () -> "Compressed size is " + compressedData.length + " while uncompressed size is " + inputData.length);
+    }
+
 }
diff --git a/vespajlib/src/test/java/com/yahoo/compress/ZstdOuputStreamTest.java b/vespajlib/src/test/java/com/yahoo/compress/ZstdOuputStreamTest.java
index 99e3130f3a3..5d35eb10215 100644
--- a/vespajlib/src/test/java/com/yahoo/compress/ZstdOuputStreamTest.java
+++ b/vespajlib/src/test/java/com/yahoo/compress/ZstdOuputStreamTest.java
@@ -7,6 +7,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 /**
  * @author bjorncs
@@ -27,4 +28,21 @@ class ZstdOuputStreamTest {
         compressor.decompress(compressedData, 0, compressedData.length, decompressedData, 0, decompressedData.length);
         assertArrayEquals(inputData, decompressedData);
     }
+
+    @Test
+    void compressed_size_is_less_than_uncompressed() throws IOException {
+        StringBuilder builder = new StringBuilder();
+        for (int i = 0; i < 100; i++) {
+            builder.append("The quick brown fox jumps over the lazy dog").append('\n');
+        }
+        byte[] inputData = builder.toString().getBytes();
+        ByteArrayOutputStream arrayOut = new ByteArrayOutputStream();
+        try (ZstdOuputStream zstdOut = new ZstdOuputStream(arrayOut)) {
+            zstdOut.write(inputData);
+        }
+        int compressedSize = arrayOut.toByteArray().length;
+        assertTrue(
+                compressedSize < inputData.length,
+                () -> "Compressed size is " + compressedSize + " while uncompressed size is " + inputData.length);
+    }
 }