> db.getCollectionInfos()
[
        {
                "name" : "foo",
                "type" : "collection",
                "options" : {

                },
                "info" : {
                        "readOnly" : false,
                        "uuid" : BinData(4,"tPsr7mDORhazM+lgLNtyIQ==")
                },
                "idIndex" : {
                        "v" : 2,
                        "key" : {
                                "_id" : 1
                        },
                        "name" : "_id_",
                        "ns" : "test.foo"
                }
        }
]

> db.runCommand({count: BinData(4,"tPsr7mDORhazM+lgLNtyIQ==")})
{ "n" : 1, "ok" : 1 }

> db.runCommand({count: BinData(4,"tPyu7mDORhazM+lgLNtyIe==")})
{
        "ok" : 0,
        "errmsg" : "UUID b4fcaeee-60ce-4616-b333-e9602cdb7221 specified in count command not found in test database",
        "code" : 26,
        "codeName" : "NamespaceNotFound"
}

> db.runCommand({count: "jklklsdjk"})
{ "n" : 0, "ok" : 1 }