ReferenceError: Can't find variable: cov_import when testing with no_module

[faxioman]

Describe the Bug

After updating wasm-bindgen-test to version 0.3.50, tests are no longer loading when run with the WASM_BINDGEN_USE_NO_MODULE=1 flag.

Steps to Reproduce

1. Update wasm-bindgen-test to version 0.3.50
2. Run tests with the WASM_BINDGEN_USE_NO_MODULE=1 flag
3. Check the developer console

Expected Behavior

Tests should load and execute successfully.

Actual Behavior

Tests fail to load and the following error appears in the developer console:

ReferenceError: Can't find variable: cov_import

The issue is in crates/cli/src/bin/wasm-bindgen-test-runner/server.rs where the {cov_import} placeholder is not being substituted in the no_modules path:

let wbg_import_script = if test_mode.no_modules() {
        String::from(
            r#"
            let Context = wasm_bindgen.WasmBindgenTestContext;
            let __wbgtest_console_debug = wasm_bindgen.__wbgtest_console_debug;
            let __wbgtest_console_log = wasm_bindgen.__wbgtest_console_log;
            let __wbgtest_console_info = wasm_bindgen.__wbgtest_console_info;
            let __wbgtest_console_warn = wasm_bindgen.__wbgtest_console_warn;
            let __wbgtest_console_error = wasm_bindgen.__wbgtest_console_error;
            {cov_import}
            let init = wasm_bindgen;
            "#,
        )
    } else {
        ...

Additional Context

The {cov_import} token in the string is likely meant to be replaced via string formatting but this substitution isn't happening, causing the JavaScript to reference an undefined variable.