@-xun/test-mock-import/dist/packages/test-mock-import/src/index.d.ts

A generic testing utility that wraps require to ensure imports are performed without caching

import type { AbsolutePath } from '@-xun/fs';
/**
 * A helper type that reduces an object type to its `default` property, if such
 * a property exists, or returns it as-is if it does not.
 */
export type AsDefault<T> = T extends {
  default: unknown;
} ? T['default'] : T;
/**
 * @see {@link isolatedImport}
 */
export type IsolatedImportOptions = {
  /**
   * By default, if `module.__esModule === true` and the only other property of
   * `module.exports` is `"default"`, then said `"default"` export will be
   * returned instead of a module object. Use `reduceToDefault` to override this
   * behavior in either direction.
   *
   * @default undefined
   */
  reduceToDefault?: boolean | undefined;
};
/**
 * Performs a CJS module import (via `require`) as if it were being imported for
 * the first time.
 *
 * Note that this function breaks the "require caching" expectation of Node.js
 * modules. Problems can arise, for example, when closing an app-wide database
 * connection in your test cleanup phase and expecting it to close for the
 * isolated module too. In this case, the isolated module has its own isolated
 * "app-wide" connection that would not actually be closed and could cause your
 * test to hang unexpectedly, even when all tests pass.
 */
export declare function isolatedImport<Module>(
/**
 * Specifier or absolute path to the module under test. Module resolution is
 * handled by `require`, therefore the specifier, if a filesystem path, should
 * never be relative and must always use unix-style separators (i.e. `/`).
 */
specifier: AbsolutePath | string, options?: IsolatedImportOptions): Module;
/**
 * Returns a function that, when invoked, performs a CJS module import (via
 * `require`) as if it were being imported for the first time. Also awaits the
 * import result and protects the caller from any calls to `process.exit` from
 * the imported module.
 *
 * Use `expectedExitCode` when the import is expected to terminate with a
 * specific exit code.
 *
 * @see {@link isolatedImport}
 */
export declare function protectedImportFactory<Module>(...[specifier, factoryOptions]: Parameters<typeof isolatedImport<Module>>): <LocalModule = Module>({
  expectedExitCode,
  reduceToDefault
}?: IsolatedImportOptions & {
  expectedExitCode?: number;
}) => Promise<LocalModule>;