diff --git a/tests/gtest/avifsvttest.cc b/tests/gtest/avifsvttest.cc
index 442c452ca5..23ffde6db0 100644
--- a/tests/gtest/avifsvttest.cc
+++ b/tests/gtest/avifsvttest.cc
@@ -1,6 +1,7 @@
 // Copyright 2025 Google LLC
 // SPDX-License-Identifier: BSD-2-Clause
 
+#include <cstdlib>
 #include <tuple>
 #include <vector>
 
@@ -29,7 +30,7 @@ TEST_P(SvtAv1Test, EncodeDecodeStillImage) {
   ASSERT_NE(avifCodecName(AVIF_CODEC_CHOICE_SVT, AVIF_CODEC_FLAG_CAN_ENCODE),
             nullptr);
   if (!testutil::Av1DecoderAvailable()) {
-    GTEST_SKIP() << "Codec unavailable, skip test.";
+    GTEST_SKIP() << "Decoder unavailable, skip test.";
   }
 
   // AVIF_CODEC_CHOICE_SVT requires dimensions to be at least 64 pixels.
@@ -72,7 +73,7 @@ TEST_P(SvtAv1Test, EncodeDecodeSequence) {
   ASSERT_NE(avifCodecName(AVIF_CODEC_CHOICE_SVT, AVIF_CODEC_FLAG_CAN_ENCODE),
             nullptr);
   if (!testutil::Av1DecoderAvailable()) {
-    GTEST_SKIP() << "Codec unavailable, skip test.";
+    GTEST_SKIP() << "Decoder unavailable, skip test.";
   }
 
   std::vector<ImagePtr> sequence;
diff --git a/tests/test_cmd_lossless.sh b/tests/test_cmd_lossless.sh
index 6b9091063b..6e6f8b5694 100755
--- a/tests/test_cmd_lossless.sh
+++ b/tests/test_cmd_lossless.sh
@@ -21,15 +21,18 @@ source $(dirname "$0")/cmd_test_common.sh
 # Input file paths.
 INPUT_PNG="${TESTDATA_DIR}/paris_icc_exif_xmp.png"
 INPUT_GRAY_PNG="${TESTDATA_DIR}/kodim03_grayscale_gamma1.6.png"
+INPUT_Y4M="${TESTDATA_DIR}/kodim03_yuv420_8bpc.y4m"
 # Output file names.
 ENCODED_FILE="avif_test_cmd_lossless_encoded.avif"
 DECODED_FILE="avif_test_cmd_lossless_decoded.png"
 DECODED_FILE_LOSSLESS="avif_test_cmd_lossless_decoded_lossless.png"
+OUT_MSG="avif_test_cmd_lossless_out_msg.txt"
 
 # Cleanup
 cleanup() {
   pushd ${TMP_DIR}
-    rm -f -- "${ENCODED_FILE}" "${DECODED_FILE}" "${DECODED_FILE_LOSSLESS}"
+    rm -f -- "${ENCODED_FILE}" "${DECODED_FILE}" "${DECODED_FILE_LOSSLESS}" \
+             "${OUT_MSG}"
   popd
 }
 trap cleanup EXIT
@@ -68,6 +71,14 @@ pushd ${TMP_DIR}
   "${AVIFENC}" -y 400 -s 10 -l "${INPUT_GRAY_PNG}" -o "${ENCODED_FILE}"
   "${AVIFDEC}" "${ENCODED_FILE}" "${DECODED_FILE_LOSSLESS}"
   "${ARE_IMAGES_EQUAL}" "${INPUT_GRAY_PNG}" "${DECODED_FILE_LOSSLESS}" 0
+
+  # SVT-AV1 supports 4:2:0 lossless starting with version 3.0.0.
+  if "${AVIFENC}" --help | grep 'svt \['; then
+    # Depending on the version, either succeeds or prints an error message.
+    "${AVIFENC}" -c svt --lossless -s 9 "${INPUT_Y4M}" "${ENCODED_FILE}"
+    "${AVIFENC}" -c svt --lossless -s 9 "${INPUT_Y4M}" "${ENCODED_FILE}" 2> "${OUT_MSG}" || \
+      grep "lossless support was added in version 3" "${OUT_MSG}"
+  fi
 popd
 
 exit 0