test: Add test for getPartsToClear

Add the test for getPartsToClear(), and fix issues found by the unit
test case with malformed input.

Tested: Verify test builds and passes.

Change-Id: I67c8bbd184e7e0c0f7f0f0fca678d1952a07cd66
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index da477d2..467c7d9 100755
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -42,6 +42,7 @@
 	../static/activation_static.cpp \
 	test_signature.cpp \
 	test_version.cpp \
+	test_item_updater_static.cpp \
 	msl_verify.cpp
 
 utest_LDADD = -lstdc++fs