test-case-shorthand-strings.js

/**
 * @fileoverview Enforce consistent usage of shorthand strings for test cases with no options
 * @author Teddy Katz
 */

'use strict';

const utils = require('../utils');

// ------------------------------------------------------------------------------
// Rule Definition
// ------------------------------------------------------------------------------

/** @type {import('eslint').Rule.RuleModule} */
module.exports = {
  meta: {
    type: 'suggestion',
    docs: {
      description:
        'Enforce consistent usage of shorthand strings for test cases with no options',
      category: 'Tests',
      recommended: false,
      url: 'https://github.com/eslint-community/eslint-plugin-eslint-plugin/tree/HEAD/docs/rules/test-case-shorthand-strings.md',
    },
    fixable: 'code',
    schema: [
      {
        description:
          'What behavior to enforce of when shorthand strings should be banned or required.',
        enum: ['as-needed', 'never', 'consistent', 'consistent-as-needed'],
      },
    ],
    messages: {
      useShorthand:
        'Use {{preferred}} for this test case instead of {{actual}}.',
    },
  },

  create(context) {
    const shorthandOption = context.options[0] || 'as-needed';
    const sourceCode = context.sourceCode || context.getSourceCode(); // TODO: just use context.sourceCode when dropping eslint < v9

    // ----------------------------------------------------------------------
    // Helpers
    // ----------------------------------------------------------------------

    /**
     * Reports test cases as necessary
     * @param {object[]} cases A list of test case nodes
     * @returns {void}
     */
    function reportTestCases(cases) {
      const caseInfoList = cases
        .map((testCase) => {
          if (
            testCase.type === 'Literal' ||
            testCase.type === 'TemplateLiteral'
          ) {
            return { node: testCase, shorthand: true, needsLongform: false };
          }
          if (testCase.type === 'ObjectExpression') {
            return {
              node: testCase,
              shorthand: false,
              needsLongform: !(
                testCase.properties.length === 1 &&
                utils.getKeyName(testCase.properties[0]) === 'code'
              ),
            };
          }
          return null;
        })
        .filter(Boolean);

      const isConsistent =
        new Set(caseInfoList.map((caseInfo) => caseInfo.shorthand)).size <= 1;
      const hasCaseNeedingLongform = caseInfoList.some(
        (caseInfo) => caseInfo.needsLongform,
      );

      caseInfoList
        .filter(
          {
            'as-needed': (caseInfo) =>
              !caseInfo.shorthand && !caseInfo.needsLongform,
            never: (caseInfo) => caseInfo.shorthand,
            consistent: isConsistent
              ? () => false
              : (caseInfo) => caseInfo.shorthand,
            'consistent-as-needed': (caseInfo) =>
              caseInfo.shorthand === hasCaseNeedingLongform,
          }[shorthandOption],
        )
        .forEach((badCaseInfo) => {
          context.report({
            node: badCaseInfo.node,
            messageId: 'useShorthand',
            data: {
              preferred: badCaseInfo.shorthand ? 'an object' : 'a string',
              actual: badCaseInfo.shorthand ? 'a string' : 'an object',
            },
            fix(fixer) {
              return fixer.replaceText(
                badCaseInfo.node,
                badCaseInfo.shorthand
                  ? `{code: ${sourceCode.getText(badCaseInfo.node)}}`
                  : sourceCode.getText(badCaseInfo.node.properties[0].value),
              );
            },
          });
        });
    }

    // ----------------------------------------------------------------------
    // Public
    // ----------------------------------------------------------------------

    return {
      Program(ast) {
        utils
          .getTestInfo(context, ast)
          .map((testRun) => testRun.valid)
          .filter(Boolean)
          .forEach(reportTestCases);
      },
    };
  },
};