security: rename SignatureSha256 to DigestSha256

Change-Id: Idabb95222d86e2541372593698ed9754156a5df2
diff --git a/tests/unit-tests/test-data.cpp b/tests/unit-tests/test-data.cpp
index f86c2bc..e7be94e 100644
--- a/tests/unit-tests/test-data.cpp
+++ b/tests/unit-tests/test-data.cpp
@@ -232,12 +232,12 @@
   BOOST_CHECK_EQUAL(a == b, true);
   BOOST_CHECK_EQUAL(a != b, false);
 
-  a = SignatureSha256();
+  a = DigestSha256();
   b = SignatureSha256WithRsa();
   BOOST_CHECK_EQUAL(a == b, false);
   BOOST_CHECK_EQUAL(a != b, true);
 
-  b = SignatureSha256();
+  b = DigestSha256();
   BOOST_CHECK_EQUAL(a == b, true);
   BOOST_CHECK_EQUAL(a != b, false);
 }