Add tests for the error cases.

Author: ericsnowcurrently

src/test/common/platform/fs-temp.unit.test.ts

@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+// tslint:disable:max-func-body-length
+
+import { expect } from 'chai';
+import * as TypeMoq from 'typemoq';
+import { TemporaryFileSystem } from '../../../client/common/platform/fs-temp';
+
+interface IDeps {
+    // tmp module
+    // tslint:disable-next-line:no-any
+    file(config: { postfix?: string }, callback?: (err: any, path: string, fd: number, cleanupCallback: () => void) => void): void;
+}
+
+suite('FileSystem - temp files', () => {
+    let deps: TypeMoq.IMock<IDeps>;
+    let temp: TemporaryFileSystem;
+    setup(() => {
+        deps = TypeMoq.Mock.ofType<IDeps>(undefined, TypeMoq.MockBehavior.Strict);
+        temp = new TemporaryFileSystem(deps.object);
+    });
+    function verifyAll() {
+        deps.verifyAll();
+    }
+
+    suite('createFile', () => {
+        test(`fails if the raw call fails`, async () => {
+            const failure = new Error('oops');
+            // prettier-ignore
+            deps.setup(d => d.file({ postfix: '.tmp' }, TypeMoq.It.isAny()))
+                .throws(failure);
+
+            const promise = temp.createFile('.tmp');
+
+            await expect(promise).to.eventually.be.rejected;
+            verifyAll();
+        });
+
+        test(`fails if the raw call "returns" an error`, async () => {
+            const failure = new Error('oops');
+            deps.setup(d => d.file({ postfix: '.tmp' }, TypeMoq.It.isAny()))
+                // tslint:disable-next-line:no-empty
+                .callback((_cfg, cb) => cb(failure, '...', -1, () => {}));
+
+            const promise = temp.createFile('.tmp');
+
+            await expect(promise).to.eventually.be.rejected;
+            verifyAll();
+        });
+    });
+});