31 lines
1.0 KiB
Python
31 lines
1.0 KiB
Python
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"""Tests for Part XIV: differential model and stability checks."""
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import numpy as np
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from fqbm.state import FQBMState
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from fqbm.system.differential_model import (
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solve_trajectory,
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check_stability,
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DifferentialParams,
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)
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def test_solve_trajectory():
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x0 = FQBMState(B=100, R=50, Loans=500, Deposits=600, E_b=50, S=1.0)
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params = DifferentialParams(monetary_shock=1.0, credit_cycle=0.01)
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t, X = solve_trajectory(x0, (0, 1), params, t_eval=np.linspace(0, 1, 11))
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assert t.shape[0] == 11
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assert X.shape == (11, 12)
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assert X[-1, 0] > X[0, 0] # B increased
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assert X[-1, 1] > X[0, 1] # R increased
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assert X[-1, 3] >= X[0, 3] # Loans
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def test_check_stability():
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x = FQBMState(R=100, Loans=1000, E_b=100)
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checks = check_stability(x, k=0.08, reserve_threshold=50, debt_gdp=0.5, r=0.05, g=0.02, primary_balance_gdp=0.02)
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assert "CR_ok" in checks
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assert "reserves_ok" in checks
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assert "debt_sustainable" in checks
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assert checks["CR_ok"] is True
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assert checks["reserves_ok"] is True
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