trilium/apps/server/src/services/search/utils/text_utils.spec.ts

import { describe, it, expect } from "vitest";
import { calculateOptimizedEditDistance, validateFuzzySearchTokens, fuzzyMatchWord } from './text_utils.js';

describe('Fuzzy Search Core', () => {
    describe('calculateOptimizedEditDistance', () => {
        it('calculates edit distance for common typos', () => {
            expect(calculateOptimizedEditDistance('hello', 'helo')).toBe(1);
            expect(calculateOptimizedEditDistance('world', 'wrold')).toBe(2);
            expect(calculateOptimizedEditDistance('cafe', 'café')).toBe(1);
            expect(calculateOptimizedEditDistance('identical', 'identical')).toBe(0);
        });

        it('handles performance safety with oversized input', () => {
            const longString = 'a'.repeat(2000);
            const result = calculateOptimizedEditDistance(longString, 'short');
            expect(result).toBeGreaterThan(2); // Should use fallback heuristic
        });
    });

    describe('validateFuzzySearchTokens', () => {
        it('validates minimum length requirements for fuzzy operators', () => {
            const result1 = validateFuzzySearchTokens(['ab'], '~=');
            expect(result1.isValid).toBe(false);
            expect(result1.error).toContain('at least 3 characters');

            const result2 = validateFuzzySearchTokens(['hello'], '~=');
            expect(result2.isValid).toBe(true);

            const result3 = validateFuzzySearchTokens(['ok'], '=');
            expect(result3.isValid).toBe(true); // Non-fuzzy operators allow short tokens
        });

        it('validates token types and empty arrays', () => {
            expect(validateFuzzySearchTokens([], '=')).toEqual({
                isValid: false,
                error: 'Invalid tokens: at least one token is required'
            });

            expect(validateFuzzySearchTokens([''], '=')).toEqual({
                isValid: false,
                error: 'Invalid tokens: empty or whitespace-only tokens are not allowed'
            });
        });
    });

    describe('fuzzyMatchWord', () => {
        it('matches words with diacritics normalization', () => {
            expect(fuzzyMatchWord('cafe', 'café')).toBe(true);
            expect(fuzzyMatchWord('naive', 'naïve')).toBe(true);
        });

        it('matches with typos within distance threshold', () => {
            expect(fuzzyMatchWord('hello', 'helo')).toBe(true);
            expect(fuzzyMatchWord('world', 'wrold')).toBe(true);
            expect(fuzzyMatchWord('test', 'tset')).toBe(true);
            expect(fuzzyMatchWord('test', 'xyz')).toBe(false);
        });

        it('handles edge cases safely', () => {
            expect(fuzzyMatchWord('', 'test')).toBe(false);
            expect(fuzzyMatchWord('test', '')).toBe(false);
            expect(fuzzyMatchWord('a', 'b')).toBe(false); // Very short tokens
        });
    });
});