keychain: extend TestKeyRingDerivation to check KeyLocators of derived keys

keychain/interface_test.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 	"math/rand"
 	"os"
+	"runtime"
 	"testing"
 	"time"
 
@@ -13,6 +14,7 @@ import (
 	"github.com/btcsuite/btcwallet/waddrmgr"
 	"github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/walletdb"
+	"github.com/davecgh/go-spew/spew"
 
 	_ "github.com/btcsuite/btcwallet/walletdb/bdb" // Required in order to create the default database.
 )
@@ -91,6 +93,14 @@ func createTestBtcWallet(coinType uint32) (func(), *wallet.Wallet, error) {
 	return cleanUp, baseWallet, nil
 }
 
+func assertEqualKeyLocator(t *testing.T, a, b KeyLocator) {
+	_, _, line, _ := runtime.Caller(1)
+	if a != b {
+		t.Fatalf("line #%v: mismatched key locators: expected %v, "+
+			"got %v", line, spew.Sdump(a), spew.Sdump(b))
+	}
+}
+
 // secretKeyRingConstructor is a function signature that's used as a generic
 // constructor for various implementations of the KeyRing interface. A string
 // naming the returned interface, a function closure that cleans up any
@@ -141,6 +151,8 @@ func TestKeyRingDerivation(t *testing.T) {
 		},
 	}
 
+	const numKeysToDerive = 10
+
 	// For each implementation constructor registered above, we'll execute
 	// an identical set of tests in order to ensure that the interface
 	// adheres to our nominal specification.
@@ -163,10 +175,16 @@ func TestKeyRingDerivation(t *testing.T) {
 					t.Fatalf("unable to derive next for "+
 						"keyFam=%v: %v", keyFam, err)
 				}
+				assertEqualKeyLocator(t,
+					KeyLocator{
+						Family: keyFam,
+						Index:  0,
+					}, keyDesc.KeyLocator,
+				)
 
-				// If we now try to manually derive the *first*
-				// key, then we should get an identical public
-				// key back.
+				// We'll now re-derive that key to ensure that
+				// we're able to properly access the key via
+				// the random access derivation methods.
 				keyLoc := KeyLocator{
 					Family: keyFam,
 					Index:  0,
@@ -176,13 +194,41 @@ func TestKeyRingDerivation(t *testing.T) {
 					t.Fatalf("unable to derive first key for "+
 						"keyFam=%v: %v", keyFam, err)
 				}
-
 				if !keyDesc.PubKey.IsEqual(firstKeyDesc.PubKey) {
-					t.Fatalf("mismatched keys: expected %v, "+
+					t.Fatalf("mismatched keys: expected %x, "+
 						"got %x",
 						keyDesc.PubKey.SerializeCompressed(),
 						firstKeyDesc.PubKey.SerializeCompressed())
 				}
+				assertEqualKeyLocator(t,
+					KeyLocator{
+						Family: keyFam,
+						Index:  0,
+					}, firstKeyDesc.KeyLocator,
+				)
+
+				// If we now try to manually derive the next 10
+				// keys (including the original key), then we
+				// should get an identical public key back and
+				// their KeyLocator information
+				// should be set properly.
+				for i := 0; i < numKeysToDerive+1; i++ {
+					keyLoc := KeyLocator{
+						Family: keyFam,
+						Index:  uint32(i),
+					}
+					keyDesc, err := keyRing.DeriveKey(keyLoc)
+					if err != nil {
+						t.Fatalf("unable to derive first key for "+
+							"keyFam=%v: %v", keyFam, err)
+					}
+
+					// Ensure that the key locator matches
+					// up as well.
+					assertEqualKeyLocator(
+						t, keyLoc, keyDesc.KeyLocator,
+					)
+				}
 
 				// If this succeeds, then we'll also try to
 				// derive a random index within the range.
@@ -191,12 +237,15 @@ func TestKeyRingDerivation(t *testing.T) {
 					Family: keyFam,
 					Index:  randKeyIndex,
 				}
-				_, err = keyRing.DeriveKey(keyLoc)
+				keyDesc, err = keyRing.DeriveKey(keyLoc)
 				if err != nil {
 					t.Fatalf("unable to derive key_index=%v "+
 						"for keyFam=%v: %v",
 						randKeyIndex, keyFam, err)
 				}
+				assertEqualKeyLocator(
+					t, keyLoc, keyDesc.KeyLocator,
+				)
 			}
 		})
 		if !success {