market_screener/tests/etf-scorer.test.ts

import test from 'node:test';
import assert from 'node:assert/strict';
import { EtfScorer } from '../server/domains/screener/scorers/EtfScorer.js';
import { ScoringConfig } from '../server/domains/shared/scoring/ScoringConfig.js';
import type { EtfMetrics } from '../server/domains/shared/types/models.model.js';

const DEFAULT_RULES = {
  gates: ScoringConfig.base.gates.ETF,
  weights: ScoringConfig.base.weights.ETF,
  thresholds: ScoringConfig.base.thresholds.ETF,
};

test('EtfScorer', async (t) => {
  await t.test('rejects ETF with high expense ratio', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.8, // Exceeds 0.2% gate
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.equal(result.label, '🔴 REJECT');
    assert.ok(result.scoreSummary.includes('Expense ratio'));
  });

  await t.test('accepts ETF with low expense ratio', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.05, // Well below 0.2% gate
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.notEqual(result.label, '🔴 REJECT');
  });

  await t.test('rejects ETF with zero expense ratio (data issue)', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0, // Zero treated as missing/invalid
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    // Zero is treated as null/missing data
    assert.ok(result);
  });

  await t.test('rejects ETF with low 5-year return', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 5, // Below 8% gate
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.equal(result.label, '🔴 REJECT');
    assert.ok(result.scoreSummary.includes('5-year return'));
  });

  await t.test('accepts ETF with strong 5-year return', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 12, // Above 8% gate
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.notEqual(result.label, '🔴 REJECT');
  });

  await t.test('rejects ETF with insufficient volume', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 500000, // Below 1M gate
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.equal(result.label, '🔴 REJECT');
    assert.ok(result.scoreSummary.includes('Volume'));
  });

  await t.test('accepts ETF with strong volume', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 10000000, // Well above 1M gate
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.notEqual(result.label, '🔴 REJECT');
  });

  await t.test('scores high-quality ETF positively', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.05, // Low
      yield: 3.0, // Decent
      volume: 20000000, // High
      fiveYearReturn: 15, // Strong
      totalAssets: 50e9, // Large
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.notEqual(result.label, '🔴 REJECT');
    assert.ok(result.audit?.passedGates);
  });

  await t.test('handles null/undefined metrics gracefully', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.1,
      yield: null,
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: null,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    // Should not crash, null values are skipped
    assert.ok(result);
  });

  await t.test('includes audit trail of gate checks', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.8,
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.ok(result.audit);
    if (!result.audit?.passedGates) {
      assert.ok(Array.isArray(result.audit?.failures));
    }
  });

  await t.test('scores yield as secondary factor', () => {
    const metricsLowYield: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 0.5, // Low yield
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const metricsHighYield: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 4.0, // High yield
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const resultLow = EtfScorer.score(metricsLowYield, DEFAULT_RULES);
    const resultHigh = EtfScorer.score(metricsHighYield, DEFAULT_RULES);

    // Both should pass gates
    assert.ok(resultLow.audit?.passedGates);
    assert.ok(resultHigh.audit?.passedGates);
  });

  await t.test('rejects ETF with multiple gate failures', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 1.0, // High
      yield: 0.5,
      volume: 100000, // Low
      fiveYearReturn: 3, // Low
      totalAssets: 100e6, // Small
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.equal(result.label, '🔴 REJECT');
    // Should have multiple failures
    if (!result.audit?.passedGates && result.audit?.failures) {
      assert.ok(result.audit.failures.length > 1);
    }
  });

  await t.test('calculates score based on thresholds', () => {
    const metricsLowReturn: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 8.5, // Just above gate
      totalAssets: 5e9,
    };

    const metricsHighReturn: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 15, // Well above gate
      totalAssets: 5e9,
    };

    const resultLow = EtfScorer.score(metricsLowReturn, DEFAULT_RULES);
    const resultHigh = EtfScorer.score(metricsHighReturn, DEFAULT_RULES);

    // Both should pass
    assert.ok(resultLow.audit?.passedGates);
    assert.ok(resultHigh.audit?.passedGates);
  });

  await t.test('penalizes low-volume ETF', () => {
    const metricsLowVolume: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 2000000, // Low but above gate
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const metricsHighVolume: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 50000000, // High volume
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const resultLow = EtfScorer.score(metricsLowVolume, DEFAULT_RULES);
    const resultHigh = EtfScorer.score(metricsHighVolume, DEFAULT_RULES);

    // Both pass gates, but high volume should score higher
    assert.ok(resultLow.audit?.passedGates);
    assert.ok(resultHigh.audit?.passedGates);
  });

  await t.test('handles extremely high expense ratio', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 5.0, // 5%!
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: 10,
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.equal(result.label, '🔴 REJECT');
  });

  await t.test('handles negative 5-year return', () => {
    const metrics: EtfMetrics = {
      expenseRatio: 0.1,
      yield: 2.5,
      volume: 5000000,
      fiveYearReturn: -5, // Negative return
      totalAssets: 5e9,
    };

    const result = EtfScorer.score(metrics, DEFAULT_RULES);
    assert.equal(result.label, '🔴 REJECT');
  });
});