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Testing Error Handling Implementation in Apache Airflow

This test suite validates the error handling functionality in Apache Airflow’s web interface. It thoroughly tests the handleError utility function which processes various types of errors including Axios errors, standard Error objects, and string messages.

Test Coverage Overview

The test suite provides comprehensive coverage of error handling scenarios in the Airflow web interface.

Tests Axios error responses with data property
Validates fallback to error messages when response data is empty
Covers standard Error object handling
Tests string error messages
Verifies fallback message behavior

Implementation Analysis

The testing approach uses Jest’s describe/test pattern with TypeScript integration. The implementation creates mock Axios error objects and validates different error scenarios systematically.

Key patterns include TypeScript type assertions, mock object creation, and explicit test case separation for different error types.

Technical Details

Testing Framework: Jest
Language: TypeScript
Key Dependencies: Axios types for error handling
Mock Objects: AxiosError, AxiosResponse
Test Structure: Single describe block with multiple test cases

Best Practices Demonstrated

The test suite exemplifies several testing best practices including comprehensive error case coverage, clear test case isolation, and proper type definitions.

Systematic error scenario testing
Clear test case documentation
Type-safe testing with TypeScript
Proper mock object construction
Fallback handling validation

apache/airflow

airflow/www/static/js/utils/handleError.test.ts

            
/*!
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 */

/* global describe, test, expect */

import type { AxiosError, AxiosResponse } from "axios";
import handleError from "./handleError";

describe("Test handleError()", () => {
  test("Returns expected results", () => {
    let description;

    // @ts-ignore
    const axiosError: AxiosError = new Error("Error message");

    axiosError.toJSON = () => ({});
    axiosError.response = {
      data: "Not available for this Executor",
      status: 400,
      statusText: "BadRequest",
      headers: {},
      config: {},
    } as AxiosResponse;
    axiosError.isAxiosError = true;

    // if response.data is defined
    description = handleError(axiosError);
    expect(description).toBe("Not available for this Executor");

    axiosError.response.data = "";

    // if it is not, use the error message
    description = handleError(axiosError);
    expect(description).toBe("Error message");

    // if error object, return the message
    description = handleError(new Error("no no"));
    expect(description).toBe("no no");

    // if string, return the string
    description = handleError("error!");
    expect(description).toBe("error!");

    // if it's undefined, use a fallback
    description = handleError(null, "fallback");
    expect(description).toBe("fallback");

    // use default if nothing is defined
    description = handleError();
    expect(description).toBe("Something went wrong.");
  });
});