fix: correct usage of execa

Author: KnisterPeter

Diff for: tests/cli-test.ts

@@ -1,6 +1,6 @@
 // tslint:disable:no-implicit-dependencies
 import test from 'ava';
-import { shell } from 'execa';
+import execa from 'execa';
 import * as fs from 'fs';
 
 function normalize(input: string): string {
@@ -12,17 +12,17 @@ function normalize(input: string): string {
 test('cli should read from stdin', async t => {
   const expected = fs.readFileSync('./tests/import-react-component.d.ts').toString();
 
-  const result = await shell(
-    `cat ./tests/import-react-component.jsx |${process.argv[0]} ./cli.js --module-name component`);
+  const result = await execa(
+    `cat ./tests/import-react-component.jsx |${process.argv[0]} ./cli.js --module-name component`, {shell: true});
 
   t.is(normalize(result.stdout), normalize(expected));
 });
 
 test('cli should read from file', async t => {
   const expected = fs.readFileSync('./tests/import-react-component.d.ts').toString();
 
-  const result = await shell(
-    `${process.argv[0]} ./cli.js --module-name component --file ./tests/import-react-component.jsx`);
+  const result = await execa(
+    `${process.argv[0]} ./cli.js --module-name component --file ./tests/import-react-component.jsx`, {shell: true});
 
   t.is(normalize(result.stdout), normalize(expected));
 });