Make the tests server handle upserts properly

[denis-zhdanov]

Problem

Consider the following client code:

import com.mongodb.client.model.Filters
import com.mongodb.client.MongoClient

private val client: MongoClient = ...

...
        val data = mapOf("key1" to "value1", "key2" to "value2")
        val filter = Filters.and(data.map {
            Filters.eq(it.key, it.value)
        })
        client.getDatabase(db).getCollection(collection).updateOne(
            filter,
            Updates.set("dummy", "dummy"),
            UpdateOptions().upsert(true)
        )

When this is executed on an empty mongo java server collection, the expectation is to have a document with fields key1, key2 and dummy. However, key1 and key2 are not inserted even though that is a legitimate mongo client api usage.

The reason is that de.bwaldvogel.mongo.backend.AbstractMongoCollection.convertSelectorToDocument() has the following code:

            if (key.startsWith("$")) {
                continue;
            }

Task

Fix the problem

[bwaldvogel]

Thanks for reporting this issue. It should be fixed with f20f3cb

[bwaldvogel]

The fix is available via v1.44.0.