shell: add explicit bash() function

src/test/shell-test.js

@@ -64,14 +64,17 @@ describe('shell', function () {
             const [error] = await safe(shell.spawn('sleep', ['20'], { timeout: 1000 }));
             expect(error.reason).to.be(BoxError.SHELL_ERROR);
         });
+    });
 
-        it('cannot exec a shell program by default', async function () {
-            const [error] = await safe(shell.exec('ls -l | wc -c', {}));
-            expect(error.reason).to.be(BoxError.SHELL_ERROR);
+    describe('bash', function () {
+        it('can bash a shell program', async function () {
+            const out = await shell.bash('ls -l | wc -c', {});
+            expect(Buffer.isBuffer(out)).to.be(true);
         });
 
-        it('cannot exec a shell program b', async function () {
-            await shell.exec('ls -l | wc -c', { shell: '/bin/bash' });
+        it('can bash a shell program', async function () {
+            const out = await shell.bash('ls -l | wc -c', { encoding: 'utf8' });
+            expect(out).to.be.a('string');
         });
     });
 });