projects/gemini-cli/packages/cli/src/test-utils/customMatchers.ts

/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/// <reference types="vitest/globals" />

/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

import type { Assertion } from 'vitest';
import { expect } from 'vitest';
import type { TextBuffer } from '../ui/components/shared/text-buffer.js';

// RegExp to detect invalid characters: backspace, and ANSI escape codes
// eslint-disable-next-line no-control-regex
const invalidCharsRegex = /[\b\x1b]/;

function toHaveOnlyValidCharacters(this: Assertion, buffer: TextBuffer) {
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const { isNot } = this as any;
  let pass = true;
  const invalidLines: Array<{ line: number; content: string }> = [];

  for (let i = 0; i < buffer.lines.length; i++) {
    const line = buffer.lines[i];
    if (line.includes('\n')) {
      pass = false;
      invalidLines.push({ line: i, content: line });
      break; // Fail fast on newlines
    }
    if (invalidCharsRegex.test(line)) {
      pass = false;
      invalidLines.push({ line: i, content: line });
    }
  }

  return {
    pass,
    message: () =>
      `Expected buffer ${isNot ? 'not ' : ''}to have only valid characters, but found invalid characters in lines:\n${invalidLines
        .map((l) => `  [${l.line}]: "${l.content}"`) /* This line was changed */
        .join('\n')}`,
    actual: buffer.lines,
    expected: 'Lines with no line breaks, backspaces, or escape codes.',
  };
}

expect.extend({
  toHaveOnlyValidCharacters,
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
} as any);

// Extend Vitest's `expect` interface with the custom matcher's type definition.
declare module 'vitest' {
  interface Assertion<T> {
    toHaveOnlyValidCharacters(): T;
  }
  interface AsymmetricMatchersContaining {
    toHaveOnlyValidCharacters(): void;
  }
}