[dev-utils/withProcRunner] fix test that swallows promise rejection (#22342)

* [dev-utils/withProcRunner] fix tests that can silently fail

* test async/sync withProcRunner functions

packages/kbn-dev-utils/src/proc_runner/__tests__/proc.sh

@@ -1,3 +0,0 @@
-#! /usr/bin/node
-
-console.log(process.argv.join(' '));

packages/kbn-dev-utils/src/proc_runner/__tests__/with_proc_runner.js

@@ -1,42 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { ToolingLog } from '../../tooling_log';
-import { withProcRunner } from '../with_proc_runner';
-
-describe('proc runner', () => {
-  function runProc({ thing = '', procs }) {
-    return new Promise(resolve => {
-      setTimeout(() => {
-        procs.run('proc', {
-          cmd: './proc',
-          args: ['these', 'are', 'words'],
-        });
-        resolve(thing);
-      }, 500);
-    });
-  }
-
-  it('passes procs to a function', async () => {
-    await withProcRunner(new ToolingLog(), async procs => {
-      await runProc({ procs });
-      await procs.stop('proc');
-    });
-  });
-});

packages/kbn-dev-utils/src/proc_runner/with_proc_runner.test.js

@@ -0,0 +1,79 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { ToolingLog } from '../tooling_log';
+import { withProcRunner } from './with_proc_runner';
+import { ProcRunner } from './proc_runner';
+
+it('passes proc runner to a function', async () => {
+  await withProcRunner(new ToolingLog(), proc => {
+    expect(proc).toBeInstanceOf(ProcRunner);
+  });
+});
+
+it('calls procRunner.teardown() if function returns synchronously', async () => {
+  let teardownSpy;
+  await withProcRunner(new ToolingLog(), proc => {
+    teardownSpy = jest.spyOn(proc, 'teardown');
+  });
+
+  expect(teardownSpy).toHaveBeenCalled();
+});
+
+it('calls procRunner.teardown() if function throw synchronous error, and rejects with the error', async () => {
+  const error = new Error('foo');
+  let teardownSpy;
+
+  await expect(
+    withProcRunner(new ToolingLog(), proc => {
+      teardownSpy = jest.spyOn(proc, 'teardown');
+      throw error;
+    })
+  ).rejects.toThrowError(error);
+
+  expect(teardownSpy).toHaveBeenCalled();
+});
+
+it('waits for promise to resolve before tearing down proc', async () => {
+  let teardownSpy;
+
+  await withProcRunner(new ToolingLog(), async proc => {
+    await new Promise(resolve => setTimeout(resolve, 500));
+    teardownSpy = jest.spyOn(proc, 'teardown');
+  });
+
+  expect(teardownSpy).not.toBe(undefined);
+  expect(teardownSpy).toHaveBeenCalled();
+});
+
+it('waits for promise to reject before tearing down proc and rejecting with the error', async () => {
+  const error = new Error('foo');
+  let teardownSpy;
+
+  await expect(
+    withProcRunner(new ToolingLog(), async proc => {
+      await new Promise(resolve => setTimeout(resolve, 500));
+      teardownSpy = jest.spyOn(proc, 'teardown');
+      throw error;
+    })
+  ).rejects.toThrowError(error);
+
+  expect(teardownSpy).not.toBe(undefined);
+  expect(teardownSpy).toHaveBeenCalled();
+});