Merge #16786: test: add unit test for wallet watch-only methods involving PubKeys

a57a1d42d52fe51e5b413a1fd3a5ef2b7a2120e3 test: add unit test for wallet watch-only methods involving PubKeys (Sebastian Falbesoner)

Pull request description:

  The motivation for this addition was to unit test the function `wallet.cpp:ExtractPubKey()` (see recent change in commit 798a589aff64b83a0844688a661f4bd987c3340c) which is however static and only indirectly available via the public methods `AddWatchOnly()`, `LoadWatchOnly()` and `RemoveWatchOnly()`. Since the first of those methods also stores the addresses to the disk, the second, simpler one was chosen which only operates in memory.

ACKs for top commit:
  Sjors:
    ACK a57a1d4
  instagibbs:
    reACK https://github.com/bitcoin/bitcoin/pull/16786/commits/a57a1d42d52fe51e5b413a1fd3a5ef2b7a2120e3
  Sjors:
    re-ACK a57a1d4

Tree-SHA512: 92a242204ab533022cd848662997372c41815b1265d07b3d96305697f801db29a5ba5668337faf4bea702bec1451972529afd6665927fb142aaf91700a338b26

1 files changed, 78 insertions, 0 deletions

diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index fc3be2b6ab..73523ca36d 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -338,6 +338,84 @@ BOOST_AUTO_TEST_CASE(LoadReceiveRequests)
     BOOST_CHECK_EQUAL(values[1], "val_rr1");
 }
 
+// Test some watch-only wallet methods by the procedure of loading (LoadWatchOnly),
+// checking (HaveWatchOnly), getting (GetWatchPubKey) and removing (RemoveWatchOnly) a
+// given PubKey, resp. its corresponding P2PK Script. Results of the the impact on
+// the address -> PubKey map is dependent on whether the PubKey is a point on the curve
+static void TestWatchOnlyPubKey(CWallet& wallet, const CPubKey& add_pubkey)
+{
+    CScript p2pk = GetScriptForRawPubKey(add_pubkey);
+    CKeyID add_address = add_pubkey.GetID();
+    CPubKey found_pubkey;
+    LOCK(wallet.cs_wallet);
+
+    // all Scripts (i.e. also all PubKeys) are added to the general watch-only set
+    BOOST_CHECK(!wallet.HaveWatchOnly(p2pk));
+    wallet.LoadWatchOnly(p2pk);
+    BOOST_CHECK(wallet.HaveWatchOnly(p2pk));
+
+    // only PubKeys on the curve shall be added to the watch-only address -> PubKey map
+    bool is_pubkey_fully_valid = add_pubkey.IsFullyValid();
+    if (is_pubkey_fully_valid) {
+        BOOST_CHECK(wallet.GetWatchPubKey(add_address, found_pubkey));
+        BOOST_CHECK(found_pubkey == add_pubkey);
+    } else {
+        BOOST_CHECK(!wallet.GetWatchPubKey(add_address, found_pubkey));
+        BOOST_CHECK(found_pubkey == CPubKey()); // passed key is unchanged
+    }
+
+    wallet.RemoveWatchOnly(p2pk);
+    BOOST_CHECK(!wallet.HaveWatchOnly(p2pk));
+
+    if (is_pubkey_fully_valid) {
+        BOOST_CHECK(!wallet.GetWatchPubKey(add_address, found_pubkey));
+        BOOST_CHECK(found_pubkey == add_pubkey); // passed key is unchanged
+    }
+}
+
+// Cryptographically invalidate a PubKey whilst keeping length and first byte
+static void PollutePubKey(CPubKey& pubkey)
+{
+    std::vector<unsigned char> pubkey_raw(pubkey.begin(), pubkey.end());
+    std::fill(pubkey_raw.begin()+1, pubkey_raw.end(), 0);
+    pubkey = CPubKey(pubkey_raw);
+    assert(!pubkey.IsFullyValid());
+    assert(pubkey.IsValid());
+}
+
+// Test watch-only wallet logic for PubKeys
+BOOST_AUTO_TEST_CASE(WatchOnlyPubKeys)
+{
+    CKey key;
+    CPubKey pubkey;
+
+    BOOST_CHECK(!m_wallet.HaveWatchOnly());
+
+    // uncompressed valid PubKey
+    key.MakeNewKey(false);
+    pubkey = key.GetPubKey();
+    assert(!pubkey.IsCompressed());
+    TestWatchOnlyPubKey(m_wallet, pubkey);
+
+    // uncompressed cryptographically invalid PubKey
+    PollutePubKey(pubkey);
+    TestWatchOnlyPubKey(m_wallet, pubkey);
+
+    // compressed valid PubKey
+    key.MakeNewKey(true);
+    pubkey = key.GetPubKey();
+    assert(pubkey.IsCompressed());
+    TestWatchOnlyPubKey(m_wallet, pubkey);
+
+    // compressed cryptographically invalid PubKey
+    PollutePubKey(pubkey);
+    TestWatchOnlyPubKey(m_wallet, pubkey);
+
+    // invalid empty PubKey
+    pubkey = CPubKey();
+    TestWatchOnlyPubKey(m_wallet, pubkey);
+}
+
 class ListCoinsTestingSetup : public TestChain100Setup
 {
 public: