Add a test case for MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED
diff --git a/tests/suites/test_suite_entropy.data b/tests/suites/test_suite_entropy.data
index 7460d74..abf36c0 100644
--- a/tests/suites/test_suite_entropy.data
+++ b/tests/suites/test_suite_entropy.data
@@ -7,6 +7,9 @@
 Entropy write/update seed file: nonexistent
 entropy_seed_file:"no_such_dir/file":MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR
 
+Entropy no sources
+entropy_no_sources:
+
 Entropy too many sources
 entropy_too_many_sources: