feat: added error to hook callback

src/hook.ts

@@ -11,7 +11,7 @@ export interface TestHookOptions {
   root?: string
 }
 
-export type TestHookCallback<T> = (output: T) => Promise<void> | void
+export type TestHookCallback<T> = (output: T & {error?: Error}) => Promise<void> | void
 
 export interface TestHook {
   (event: string, hookOpts: object, opts: TestHookOptions & {stdout: true, stderr: true}, fn: TestHookCallback<{stdout: string, stderr: string}>): void
@@ -34,11 +34,13 @@ export const testHook: TestHook = (
     const engine = new Engine()
     await engine.load(opts.root || module.parent!.parent!.filename)
     const run = () => engine.runHook(event, hookOpts)
+    let err
     if (typeof opts.exit === 'number') {
       try {
         await run()
         throw new Error(`Expected hook to exit with code ${opts.exit} but it ran without exiting`)
-      } catch (err) {
+      } catch (e) {
+        err = e
         if (!err['cli-ux'] || typeof err['cli-ux'].exit !== 'number') throw err
         if (err['cli-ux'].exit !== opts.exit) {
           throw new Error(`Expected hook to exit with ${opts.exit} but exited with ${err['cli-ux'].exit}`)
@@ -49,6 +51,7 @@ export const testHook: TestHook = (
     if (typeof opts.stderr === 'string') expect(output.stderr).to.equal(opts.stderr)
     if (!fn) return
     let o: any = {}
+    o.error = err
     if (opts.stdout) o.stdout = output.stdout
     if (opts.stderr) o.stderr = output.stderr
     await fn(o)