The mongo-go-driver tests currently use a mixture of "go.mongodb.org/mongo-driver/internal/testutil/assert", "github.com/stretchr/testify/assert" to assert things in the tests. Those packages have a similar but slightly different API that is confusing to read/use together. The "github.com/stretchr/testify/assert" package is a more complete API and is a standard assertion API in Go projects, so prefer that package over the internal package.

Questions:

• Is "github.com/stretchr/testify/assert" the best package or is there another package that has superseded it?

Definition of done:

• Vendor a useful subset of the "github.com/stretchr/testify/assert" and "github.com/stretchr/testify/require" packages somewhere in an internal package.
• Replace all uses of the "go.mongodb.org/mongo-driver/internal/testutil/assert" package with the vendored "github.com/stretchr/testify/assert"/"github.com/stretchr/testify/require" APIs.
• Remove the testutil/assert package.