Updated equals and hashcode for MongoCredential

userName can now be null so need to null check first.

JAVA-2375

Author: rozza

driver-core/src/main/com/mongodb/MongoCredential.java

@@ -408,7 +408,7 @@ public boolean equals(final Object o) {
         if (!source.equals(that.source)) {
             return false;
         }
-        if (!userName.equals(that.userName)) {
+        if (userName != null ? !userName.equals(that.userName) : that.userName != null) {
             return false;
         }
         if (!mechanismProperties.equals(that.mechanismProperties)) {
@@ -421,7 +421,7 @@ public boolean equals(final Object o) {
     @Override
     public int hashCode() {
         int result = mechanism != null ? mechanism.hashCode() : 0;
-        result = 31 * result + userName.hashCode();
+        result = 31 * result + (userName != null ? userName.hashCode() : 0);
         result = 31 * result + source.hashCode();
         result = 31 * result + (password != null ? Arrays.hashCode(password) : 0);
         result = 31 * result + mechanismProperties.hashCode();

driver-core/src/test/unit/com/mongodb/MongoCredentialSpecification.groovy

@@ -280,4 +280,28 @@ class MongoCredentialSpecification extends Specification {
 
         !credentialOne.toString().contains(password)
     }
+
+    def 'testEqualsAndHashCode'() {
+        expect:
+        credential() == credential()
+        credential().hashCode() == credential().hashCode()
+
+        where:
+        credential << [
+            { MongoCredential.createCredential('user', 'database', 'pwd'.toCharArray()) },
+            { MongoCredential.createCredential('user', 'database', 'pwd'.toCharArray()).withMechanismProperty('foo', 'bar') },
+            { MongoCredential.createMongoCRCredential('user', 'database', 'pwd'.toCharArray()) },
+            { MongoCredential.createMongoCRCredential('user', 'database', 'pwd'.toCharArray()).withMechanismProperty('foo', 'bar') },
+            { MongoCredential.createPlainCredential('user', '$external', 'pwd'.toCharArray()) },
+            { MongoCredential.createPlainCredential('user', '$external', 'pwd'.toCharArray()).withMechanismProperty('foo', 'bar') },
+            { MongoCredential.createScramSha1Credential('user', '$external', 'pwd'.toCharArray()) },
+            { MongoCredential.createScramSha1Credential('user', '$external', 'pwd'.toCharArray()).withMechanismProperty('foo', 'bar') },
+            { MongoCredential.createGSSAPICredential('user') },
+            { MongoCredential.createGSSAPICredential('user').withMechanismProperty('foo', 'bar') },
+            { MongoCredential.createMongoX509Credential('user') },
+            { MongoCredential.createMongoX509Credential('user').withMechanismProperty('foo', 'bar') },
+            { MongoCredential.createMongoX509Credential() },
+            { MongoCredential.createMongoX509Credential().withMechanismProperty('foo', 'bar') },
+        ]
+    }
 }