Configure test runner to use vendor directory

In my workspace project we use vendored dependencies in the vendor directory, but we do not add the replace-with configuration in the .cargo/config.toml because doing so effectively cuts off all access to crates.io. Instead we use aliases for build and test that set the replacement for those commands e.g.:

test-vendor = [
    "test",
    "--config",
    "source.vendored-sources.directory='vendor'",
    "--config",
    "source.crates-io.replace-with='vendored-sources'",
    "--locked",
]

I'd like to be able to replicate something like this in rust-analyzer in VS Code for running tests.

What I've tried:

• Creating a supplemental config.vendor.toml with the required source settings and setting --config .cargo/config.vendor.toml in rust-analyzer.cargo.extraArgs
• Setting the --config source.vendored-sources... etc, in rust-analyzer.cargo.extraArgs
• Setting:

    "rust-analyzer.cargo.extraEnv": {
        "CARGO_SOURCE_VENDORED_SOURCES_DIRECTORY": "vendor",
        "CARGO_SOURCE_CRATES_IO_REPLACE_WITH": "vendored-sources"
    }

• Setting:

    "rust-analyzer.cargo.cfgs": {
        "source.crates-io.replace-with": "vendored-sources",
        "source.vendored-sources.directory": "vendor"
    }

• Creating a launch.json and adding either the --config with a path or with the key/value pairs to the cargo args tables.

Is there any way of specifying additional arguments to pass to the invocation of cargo test?

No source files or tests are named. Start by reading rust-analyzer's cargo configuration and VS Code test-runner documentation, then trace how cargo test is invoked and how cargo.extraArgs is applied. Done means users can supply additional cargo test arguments, including the requested --config settings, for test runs.