Forgot to add the error tests

packages/backend-common/src/errors.test.ts

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed 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 * as errors from './errors';
+
+describe('errors', () => {
+  it('extends Error properly', () => {
+    for (const [name, E] of Object.entries(errors)) {
+      const error = new E('abcdef');
+      expect(error.name).toBe(name);
+      expect(error.message).toBe('abcdef');
+      expect(error.stack).toContain(__filename);
+      expect(error.toString()).toContain(name);
+      expect(error.toString()).toContain('abcdef');
+    }
+  });
+
+  it('supports causes', () => {
+    const cause = new Error('hello');
+    for (const [, E] of Object.entries(errors)) {
+      const error = new E('abcdef', cause);
+      expect(error.cause).toBe(cause);
+      expect(error.toString()).toContain(
+        `${name}: abcdef; caused by Error: hello`,
+      );
+    }
+  });
+});