Verify op_ is not a nullptr

If op_ is a nullptr, the test runner can SIGSEGV.

Test: manual, atest EncryptionOperationsTest#TripleDesCbcPkcs7PaddingCorrupted
Bug: None

Signed-off-by: Brian J Murray <brianjmurray@google.com>
Change-Id: Ibdd6139952ca8bc83ac1a82202839feee39562e1
diff --git a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
index 3695f1e..02462fc 100644
--- a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
@@ -537,6 +537,9 @@
     Status result;
     if (!output) return ErrorCode::UNEXPECTED_NULL_POINTER;
 
+    EXPECT_NE(op_, nullptr);
+    if (!op_) return ErrorCode::UNEXPECTED_NULL_POINTER;
+
     std::vector<uint8_t> o_put;
     result = op_->update(vector<uint8_t>(input.begin(), input.end()), {}, {}, &o_put);