diff --git a/tests/unit-tests/run-unit-tests.sh b/tests/unit-tests/run-unit-tests.sh
index ea59569..f6487a4 100755
--- a/tests/unit-tests/run-unit-tests.sh
+++ b/tests/unit-tests/run-unit-tests.sh
@@ -16,7 +16,7 @@ sudo dnf builddep -y osbuild-composer.spec
 cd "${TMT_SOURCE_DIR}"
 
 # Extract the Source0 basename without extension
-SRC_DIR=$(spectool --source 0 osbuild-composer.spec | sed 's/.\+\(osbuild-composer-[0-9]\+\)\.tar\.gz/\1/')
+SRC_DIR=$(spectool --source 0 osbuild-composer.spec | sed -E 's|.*/([^/]*)\.tar\.gz$|\1|')
 
 # Move to the extracted sources directory (patches are applied by default)
 cd "${SRC_DIR}"