Apollo Server Testing Utilities (Legacy)

This `apollo-server-testing` package provides utilities specifically designed for testing applications built with older versions of Apollo Server (v2 and v3). Its primary export, `createTestClient`, wraps the `ApolloServer.executeOperation` method to allow direct GraphQL operation execution against an `ApolloServer` instance without spinning up a full HTTP server. The package `apollo-server-testing` is currently at version `2.25.3` and was last published over four years ago. It is considered abandoned for new development, as the current major versions of Apollo Server (v4 and v5, under the `@apollo/server` package) integrate testing utilities directly via `server.executeOperation` or provide `@apollo/server/testing` where applicable. This package is solely relevant for maintaining legacy projects still on `apollo-server` v2 or v3, which are both officially end-of-life.