Configure test runner to use vendor directory

[nine9ths]

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?