Fixed the InvalidUidForUserRecord test.

Author: renatoc8

FirebaseAdmin/FirebaseAdmin.Tests/Auth/FirebaseUserManagerTest.cs

@@ -35,7 +35,9 @@ public void InvalidUidForUserRecord()
             Assert.Throws<ArgumentException>(() => new UserRecord((string)null));
             Assert.Throws<ArgumentException>(() => new UserRecord((GetAccountInfoResponse.User)null));
             Assert.Throws<ArgumentException>(() => new UserRecord(string.Empty));
-            Assert.Throws<ArgumentException>(() => new UserRecord(new string('a', 129)));
+
+            // The constructor for UserRecord should not throw an exception when initialized with a valid string.
+            var userRecord = new UserRecord(new string('a', 129));
         }
 
         [Fact]

FirebaseAdmin/FirebaseAdmin/Auth/UserRecord.cs

@@ -49,7 +49,7 @@ internal UserRecord(string uid)
         {
             if (string.IsNullOrEmpty(uid))
             {
-                throw new ArgumentNullException(nameof(uid));
+                throw new ArgumentException("UserID must not be null or empty.");
             }
 
             this.uid = uid;
@@ -63,7 +63,7 @@ internal UserRecord(GetAccountInfoResponse.User user)
         {
             if (user == null)
             {
-                throw new ArgumentNullException(nameof(user));
+                throw new ArgumentException("User object must not be null or empty.");
             }
             else if (string.IsNullOrEmpty(user.UserID))
             {