Ensure speculative auth uses the credentials auth source. (#781)

JAVA-4290

Author: rozza

driver-core/src/main/com/mongodb/internal/connection/ScramShaAuthenticator.java

@@ -99,7 +99,7 @@ public BsonDocument createSpeculativeAuthenticateCommand(final InternalConnectio
         try {
             speculativeSaslClient = createSaslClient(connection.getDescription().getServerAddress());
             BsonDocument startDocument = createSaslStartCommandDocument(speculativeSaslClient.evaluateChallenge(new byte[0]))
-                    .append("db", new BsonString("admin"));
+                    .append("db", new BsonString(getMongoCredential().getSource()));
             appendSaslStartOptions(startDocument);
             return startDocument;
         } catch (Exception e) {

driver-core/src/test/unit/com/mongodb/internal/connection/InternalStreamConnectionInitializerSpecification.groovy

@@ -540,7 +540,7 @@ class InternalStreamConnectionInitializerSpecification extends Specification {
                                 "mechanism: '${mechanism}', db: \"\$external\" } }" :
                         'speculativeAuthenticate: { saslStart: 1, ' +
                                 "mechanism: '${mechanism}', payload: BinData(0, '${encode64(firstClientChallenge)}'), " +
-                                'db: "admin", options: { skipEmptyExchange: true } } }')
+                                'db: "database", options: { skipEmptyExchange: true } } }')
 
         BsonDocument.parse(isMaster)
     }

driver-core/src/test/unit/com/mongodb/internal/connection/ScramShaAuthenticatorSpecification.groovy

@@ -78,7 +78,7 @@ class ScramShaAuthenticatorSpecification extends Specification {
         def firstClientChallenge = 'n,,n=user,r=fyko+d2lbbFgONRv9qkxdawL'
         def expectedSpeculativeAuthenticateCommand = BsonDocument.parse('{ saslStart: 1, mechanism: "SCRAM-SHA-1", '
                 + "payload: BinData(0, '${encode64(firstClientChallenge)}'), "
-                + 'db: "admin", options: { skipEmptyExchange: true }}')
+                + 'db: "database", options: { skipEmptyExchange: true }}')
         def serverResponse = 'r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,s=QSXCR+Q6sek8bf92,i=4096'
         def speculativeAuthenticateResponse =
                 BsonDocument.parse("{ conversationId: 1, payload: BinData(0, '${encode64(serverResponse)}'), done: false }")
@@ -132,7 +132,7 @@ class ScramShaAuthenticatorSpecification extends Specification {
         def firstClientChallenge = 'n,,n=user,r=rOprNGfwEbeRWgbNEkqO'
         def expectedSpeculativeAuthenticateCommand = BsonDocument.parse('{ saslStart: 1, mechanism: "SCRAM-SHA-256", '
                 + "payload: BinData(0, '${encode64(firstClientChallenge)}'), "
-                + 'db: "admin", options: { skipEmptyExchange: true }}')
+                + 'db: "database", options: { skipEmptyExchange: true }}')
         def serverResponse = 'r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,s=W22ZaJ0SNY7soEsUEjb6gQ==,i=4096'
         def speculativeAuthenticateResponse =
                 BsonDocument.parse("{ conversationId: 1, payload: BinData(0, '${encode64(serverResponse)}'), done: false }")