Realm manager for Swift 5.0

RealmManager.swift

import Realm
import RealmSwift

class RealmManager {
    static let shared = RealmManager()

    private func getRealm() -> Realm {
        if let _ = NSClassFromString("XCTest") {
            return try! Realm(configuration: Realm.Configuration(fileURL: nil, inMemoryIdentifier: "test", encryptionKey: nil, readOnly: false, schemaVersion: 0, migrationBlock: nil, objectTypes: nil))
        } else {
            return try! Realm();
        }
    }

    func objects<T: Object>(_ type: T.Type, predicate: NSPredicate? = nil) -> Results<T>? {
        if !isRealmAccessible() { return nil }

        let realm = getRealm()
        realm.refresh()

        return predicate == nil ? realm.objects(type) : realm.objects(type).filter(predicate!)
    }

    func object<T: Object>(_ type: T.Type, key: Any) -> T? {
        if !isRealmAccessible() { return nil }

        let realm = getRealm()
        realm.refresh()

        return realm.object(ofType: type, forPrimaryKey: key)
    }

    func add<T: Object>(_ data: [T], update: Bool = true) {
        if !isRealmAccessible() { return }

        let realm = getRealm()
        realm.refresh()

        if realm.isInWriteTransaction {
            realm.add(data, update: update)
        } else {
            try? realm.write {
                realm.add(data, update: update)
            }
        }
    }

    func add<T: Object>(_ data: T, update: Bool = true) {
        add([data], update: update)
    }

    func runTransaction(action: () -> Void) {
        if !isRealmAccessible() { return }

        let realm = getRealm()
        realm.refresh()

        try? realm.write {
            action()
        }
    }

    func delete<T: Object>(_ data: [T]) {
        let realm = getRealm()
        realm.refresh()
        try? realm.write { realm.delete(data) }
    }

    func delete<T: Object>(_ data: T) {
        delete([data])
    }

    func clearAllData() {
        if !isRealmAccessible() { return }

        let realm = getRealm()
        realm.refresh()
        try? realm.write { realm.deleteAll() }
    }
}

extension RealmManager {
    func isRealmAccessible() -> Bool {
        do { _ = try Realm() } catch {
            print("Realm is not accessible")
            return false
        }
        return true
    }

    func configureRealm() {
        let config = RLMRealmConfiguration.default()
        config.deleteRealmIfMigrationNeeded = true
        RLMRealmConfiguration.setDefault(config)
    }
}

So how do you update an object with this manager?
If you do that and call add method the app will crash because the object is persisted by Realm and can't be updated outside of a write transaction.
Should I use the runTransaction method?

@SlavchoPetkovski You'd want to do something along the lines of
do {
try RealmManager.shared.getRealm().write({
})
} catch {
}