Add a unit test for applypatch_check

If no sha1 is specified, applypatch_check should pass as long as
the file content loads successfully. Add a unit case acccordingly.

Test: Unit tests passed
Bug: 32243751
Change-Id: I8c013be67c197d2935e11cf6acc59fb9b943cfd9
diff --git a/tests/component/applypatch_test.cpp b/tests/component/applypatch_test.cpp
index 75f2e10..908a9f5 100644
--- a/tests/component/applypatch_test.cpp
+++ b/tests/component/applypatch_test.cpp
@@ -200,6 +200,11 @@
 TemporaryFile* ApplyPatchFullTest::output_f;
 std::string ApplyPatchFullTest::output_loc;
 
+TEST_F(ApplyPatchTest, CheckModeSkip) {
+    std::vector<std::string> sha1s;
+    ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));
+}
+
 TEST_F(ApplyPatchTest, CheckModeSingle) {
     std::vector<std::string> sha1s = { old_sha1 };
     ASSERT_EQ(0, applypatch_check(&old_file[0], sha1s));