AI-Driven Test Generation
& Self-Healing Tests

# ================================================================
# S11409 - Sesi 10: Mutation Testing + AI-Generated Tests
# Dosen: Riadi Marta Dinata, S.Ti., M.Kom. | ISTN Jakarta
# pip install pytest mutmut
# ================================================================

# ── kalkulator_kredit.py ──────────────────────────────────────
class KalkulatorKredit:
    """Kalkulator cicilan kredit sederhana (OJK compliant)"""

    def hitung_cicilan(self, pokok, bunga_tahunan, tenor_bulan):
        if pokok <= 0:
            raise ValueError("Pokok pinjaman harus positif")
        if bunga_tahunan < 0 or bunga_tahunan > 100:
            raise ValueError("Bunga harus antara 0 dan 100")
        if tenor_bulan <= 0:
            raise ValueError("Tenor harus lebih dari 0 bulan")
        bunga_per_bulan = bunga_tahunan / 12 / 100
        total_bunga = pokok * bunga_per_bulan * tenor_bulan
        cicilan = (pokok + total_bunga) / tenor_bulan
        return round(cicilan, 2)

    def cek_kelayakan(self, penghasilan_bulanan, cicilan):
        """Aturan OJK: cicilan maks 30% dari penghasilan"""
        if penghasilan_bulanan <= 0:
            raise ValueError("Penghasilan harus positif")
        rasio = cicilan / penghasilan_bulanan
        return rasio <= 0.30

# ── tests/test_kredit_ai_generated.py ─────────────────────────
import pytest
# from kalkulator_kredit import KalkulatorKredit

@pytest.fixture
def kalkulator():
    return KalkulatorKredit()

class TestHitungCicilan:
    """Test suite mensimulasikan output AI / GitHub Copilot"""

    def test_cicilan_standar(self, kalkulator):
        # 12jt, 12%/thn, 12bln → cicilan 1.120.000
        cicilan = kalkulator.hitung_cicilan(12_000_000, 12, 12)
        assert cicilan == 1_120_000.0

    def test_cicilan_tanpa_bunga(self, kalkulator):
        cicilan = kalkulator.hitung_cicilan(6_000_000, 0, 12)
        assert cicilan == 500_000.0

    # BVA lengkap yang dihasilkan AI
    @pytest.mark.parametrize("pokok,bunga,tenor,valid", [
        (1,          0,   1, True),   # min boundary valid
        (0,         12,  12, False),  # zero → invalid
        (-1,        12,  12, False),  # negatif → invalid
        (1_000_000,  0,  12, True),   # bunga min valid
        (1_000_000, 100, 12, True),   # bunga max valid
        (1_000_000, 101, 12, False),  # bunga > max → invalid
        (1_000_000, -1,  12, False),  # bunga negatif → invalid
        (1_000_000, 12,   1, True),   # tenor min valid
        (1_000_000, 12,   0, False),  # tenor zero → invalid
    ])
    def test_validasi_boundary(self, kalkulator, pokok, bunga, tenor, valid):
        if valid:
            assert kalkulator.hitung_cicilan(pokok, bunga, tenor) > 0
        else:
            with pytest.raises(ValueError):
                kalkulator.hitung_cicilan(pokok, bunga, tenor)

    def test_layak_tepat_30pct(self, kalkulator):
        # Boundary: tepat 30% → LAYAK
        assert kalkulator.cek_kelayakan(10_000_000, 3_000_000) == True

    def test_tidak_layak_31pct(self, kalkulator):
        # Boundary: 31% → TIDAK LAYAK
        assert kalkulator.cek_kelayakan(10_000_000, 3_100_000) == False


# ── SIMULASI MUTATION TESTING ANALYSIS ───────────────────────
def simulate_mutation_analysis():
    mutants = [
        {"id":1, "desc":"pokok <= 0  →  pokok < 0",         "killed": True},
        {"id":2, "desc":"bunga/12/100  →  bunga/12*100",     "killed": True},
        {"id":3, "desc":"rasio <= 0.30  →  rasio < 0.30",    "killed": True},
        {"id":4, "desc":"round(cicilan, 2)  →  cicilan",      "killed": False},
        {"id":5, "desc":"tenor_bulan <= 0  →  tenor_bulan < 0","killed": True},
        {"id":6, "desc":"cicilan * tenor  →  cicilan + tenor","killed": True},
    ]
    killed = sum(1 for m in mutants if m["killed"])
    total  = len(mutants)
    score  = killed / total * 100

    print("=" * 55)
    print("    MUTATION TESTING RESULTS")
    print("=" * 55)
    for m in mutants:
        status = "KILLED   " if m["killed"] else "SURVIVED "
        icon   = "OK" if m["killed"] else "!!"
        print(f"  [{m['id']}] [{icon}] {status} | {m['desc']}")

    print(f"\n  Killed / Total : {killed}/{total}")
    print(f"  Mutation Score : {score:.1f}%")
    grade = "GOOD" if score >= 80 else ("FAIR" if score >= 60 else "POOR")
    print(f"  Status         : {grade}")
    print("\n  Tip: Mutant #4 survived — tambahkan test yang")
    print("  memverifikasi presisi 2 desimal pada cicilan.")
    return score

if __name__ == "__main__":
    simulate_mutation_analysis()
    print("\nJalankan pytest : pytest tests/ -v")
    print("Jalankan mutmut : mutmut run && mutmut results")