anagram-generator/tests/letter_removal_tests.rs

use anagram_generator::{
    analyzer::PronounceabilityAnalyzer, generator::AnagramGenerator, generator::GenerationConfig,
    generator::LetterRemovalStrategy,
};
use rand::SeedableRng;
use rand::rngs::StdRng;

#[test]
fn test_letter_removal_disabled_by_default() {
    let config = GenerationConfig::default();
    assert_eq!(config.letter_removal, LetterRemovalStrategy::None);
}

#[test]
fn test_letter_removal_can_be_enabled() {
    let config = GenerationConfig::default().allow_removing_letters(3);
    assert_eq!(
        config.letter_removal,
        LetterRemovalStrategy::Adaptive { max_removals: 3 }
    );
}

#[test]
fn test_generation_without_removal_produces_same_length() {
    let rng = StdRng::seed_from_u64(42);
    let scorer = PronounceabilityAnalyzer::with_defaults();
    let mut generator = AnagramGenerator::new(rng, scorer);

    let source = "difficult";
    let config = GenerationConfig::new(0, 1000);
    let anagrams = generator.generate(source, 5, &config);

    for anagram in &anagrams {
        assert_eq!(anagram.text().len(), source.len());
    }
}

#[test]
fn test_generation_with_removal_may_produce_shorter_words() {
    let rng = StdRng::seed_from_u64(42);
    let scorer = PronounceabilityAnalyzer::with_defaults();
    let mut generator = AnagramGenerator::new(rng, scorer);

    let source = "xyzqwbcdfg"; // Very hard to pronounce word
    let config = GenerationConfig::new(60, 5000).allow_removing_letters(4);
    let anagrams = generator.generate(source, 5, &config);

    // With letter removal enabled, some results might be shorter
    let has_shorter = anagrams.iter().any(|a| a.text().len() < source.len());
    // Due to randomness and the difficult source word, we expect some shorter results
    assert!(has_shorter || anagrams.is_empty());
}

#[test]
fn test_letter_removal_improves_pronounceability() {
    let rng1 = StdRng::seed_from_u64(42);
    let rng2 = StdRng::seed_from_u64(42);
    let scorer1 = PronounceabilityAnalyzer::with_defaults();
    let scorer2 = PronounceabilityAnalyzer::with_defaults();
    let mut generator_without = AnagramGenerator::new(rng1, scorer1);
    let mut generator_with = AnagramGenerator::new(rng2, scorer2);

    let source = "bcdfghjklm"; // No vowels, very hard to pronounce
    let config_without = GenerationConfig::new(40, 10000);
    let config_with = GenerationConfig::new(40, 10000).allow_removing_letters(5);

    let anagrams_without = generator_without.generate(source, 10, &config_without);
    let anagrams_with = generator_with.generate(source, 10, &config_with);

    // With letter removal, we should be able to generate more anagrams
    // or achieve higher scores on average
    if !anagrams_with.is_empty() && !anagrams_without.is_empty() {
        let avg_score_without: f32 = anagrams_without
            .iter()
            .map(|a| a.score().value() as f32)
            .sum::<f32>()
            / anagrams_without.len() as f32;

        let avg_score_with: f32 = anagrams_with
            .iter()
            .map(|a| a.score().value() as f32)
            .sum::<f32>()
            / anagrams_with.len() as f32;

        // Letter removal should help achieve better or equal scores
        assert!(
            avg_score_with >= avg_score_without || anagrams_with.len() > anagrams_without.len()
        );
    }
}

#[test]
fn test_letter_removal_respects_max_removals() {
    let rng = StdRng::seed_from_u64(42);
    let scorer = PronounceabilityAnalyzer::with_defaults();
    let mut generator = AnagramGenerator::new(rng, scorer);

    let source = "testing";
    let max_removals = 2;
    let config = GenerationConfig::new(0, 1000).allow_removing_letters(max_removals);
    let anagrams = generator.generate(source, 20, &config);

    // All anagrams should have at least (source.len() - max_removals) letters
    let min_length = source.len() - max_removals;
    for anagram in &anagrams {
        assert!(
            anagram.text().len() >= min_length,
            "Anagram '{}' is too short (min: {})",
            anagram.text(),
            min_length
        );
    }
}

#[test]
fn test_letter_removal_maintains_min_word_length() {
    let rng = StdRng::seed_from_u64(42);
    let scorer = PronounceabilityAnalyzer::with_defaults();
    let mut generator = AnagramGenerator::new(rng, scorer);

    let source = "abc";
    let config = GenerationConfig::new(0, 1000).allow_removing_letters(10); // More than word length
    let anagrams = generator.generate(source, 10, &config);

    // Should maintain at least 2 characters (word length - 1)
    for anagram in &anagrams {
        assert!(
            !anagram.text().is_empty(),
            "Anagram '{}' is too short",
            anagram.text()
        );
    }
}

#[test]
fn test_letter_removal_with_good_word() {
    let rng = StdRng::seed_from_u64(42);
    let scorer = PronounceabilityAnalyzer::with_defaults();
    let mut generator = AnagramGenerator::new(rng, scorer);

    let source = "example"; // Already pronounceable
    let config = GenerationConfig::new(70, 1000).allow_removing_letters(2);
    let anagrams = generator.generate(source, 10, &config);

    // With an already good word, letter removal might not be necessary
    // But it should still work and produce results
    assert!(!anagrams.is_empty());
    for anagram in &anagrams {
        assert!(anagram.score().value() >= 70);
    }
}

#[test]
fn test_config_builder_with_letter_removal() {
    let config = GenerationConfig::default()
        .with_min_score(60)
        .with_max_attempts(5000)
        .allow_removing_letters(3);

    assert_eq!(config.min_score.value(), 60);
    assert_eq!(config.max_attempts_per_anagram, 5000);
    assert_eq!(
        config.letter_removal,
        LetterRemovalStrategy::Adaptive { max_removals: 3 }
    );
}

#[test]
fn test_letter_removal_strategy_with_method() {
    let config = GenerationConfig::default()
        .with_letter_removal(LetterRemovalStrategy::Adaptive { max_removals: 5 });

    assert_eq!(
        config.letter_removal,
        LetterRemovalStrategy::Adaptive { max_removals: 5 }
    );
}