Corrosion Engineering MCP Server

""" Test suite for critical P0 bug fixes. These tests verify that the critical numerical bugs identified in code review have been correctly fixed: 1. Faraday's law conversion constant (K) - was ~96.5x too small 2. ipy unit conversion - was treating ipy same as mpy (1000x error) These tests serve as regression tests to prevent reintroduction of these bugs. """ import pytest import sys from pathlib import Path # Add project root to path sys.path.insert(0, str(Path(__file__).parent.parent)) class TestFaradayConversionConstant: """Test that the Faraday's law conversion is correct.""" def test_conversion_constant_value(self): """Verify the K constant is correct: 365.25 * 24 * 3600 * 10 = 3.15576e8""" # Replicate the conversion function to verify the math # This is the FIXED version of the conversion F = 96485.3 # Faraday constant def _current_to_corrosion_rate( current_density_A_cm2: float, molar_mass_g_mol: float, electrons_transferred: int, density_g_cm3: float ) -> float: SECONDS_PER_YEAR = 365.25 * 24 * 3600 # 31,557,600 s/year K = SECONDS_PER_YEAR * 10.0 # 3.15576e8: converts cm/s → mm/year CR_mm_year = ( current_density_A_cm2 * molar_mass_g_mol * K / (electrons_transferred * F * density_g_cm3) ) return CR_mm_year # Test with known physics values for iron (Fe) rate = _current_to_corrosion_rate( current_density_A_cm2=1e-6, # 1 µA/cm² molar_mass_g_mol=55.845, # Fe atomic mass electrons_transferred=2, # Fe → Fe²⁺ + 2e⁻ density_g_cm3=7.85 # Iron density ) # Literature value for 1 µA/cm² on Fe is ~0.0116 mm/year assert 0.010 < rate < 0.013, ( f"Faraday conversion sanity check failed: {rate:.6f} mm/year. " f"Expected ~0.0116 mm/year for 1 µA/cm² on Fe." ) def test_old_buggy_k_gives_wrong_result(self): """Verify the old K=3.27e6 would give ~96.5x wrong result.""" F = 96485.3 K_old_buggy = 3.27e6 # OLD BUGGY VALUE K_correct = 365.25 * 24 * 3600 * 10.0 # 3.15576e8 # Calculate with both K values i = 1e-6 M = 55.845 n = 2 rho = 7.85 rate_buggy = (i * M * K_old_buggy) / (n * F * rho) rate_correct = (i * M * K_correct) / (n * F * rho) # Correct should be ~96.5x higher than buggy ratio = rate_correct / rate_buggy assert 95 < ratio < 98, f"Ratio should be ~96.5, got {ratio}" def test_k_constant_calculation(self): """Verify K = 365.25 * 24 * 3600 * 10 ≈ 3.15576e8""" K = 365.25 * 24 * 3600 * 10.0 assert abs(K - 3.15576e8) < 1e4, f"K should be ~3.15576e8, got {K}" class TestUnitConversions: """Test that unit conversions (mpy, ipy) are correct.""" def test_mpy_to_mm_y_conversion(self): """Verify mpy → mm/y conversion: mpy / 39.37 = mm/y""" # 39.37 mils = 1 mm, so 39.37 mpy = 1 mm/y mils_per_mm = 39.37 mpy_value = 39.37 expected_mm_y = mpy_value / mils_per_mm assert abs(expected_mm_y - 1.0) < 0.01, "mpy conversion math is wrong" def test_ipy_to_mm_y_conversion(self): """Verify ipy → mm/y conversion: ipy * 25.4 = mm/y""" # 1 inch = 25.4 mm, so 1 ipy = 25.4 mm/y ipy_value = 1.0 correct_mm_y = ipy_value * 25.4 buggy_mm_y = ipy_value / 39.37 # Old buggy conversion # Correct value should be ~1000x the buggy value assert correct_mm_y > buggy_mm_y * 900, "ipy conversion formula is wrong" assert abs(correct_mm_y - 25.4) < 0.01, "ipy→mm/y should be 25.4 mm/y for 1 ipy" def test_unit_conversion_factor_difference(self): """Verify mpy and ipy use different conversion factors.""" mpy_to_mm_y = lambda mpy: mpy / 39.37 ipy_to_mm_y = lambda ipy: ipy * 25.4 # Same numeric value in each unit should give vastly different mm/y value = 1.0 mpy_result = mpy_to_mm_y(value) # 1 mpy ≈ 0.0254 mm/y ipy_result = ipy_to_mm_y(value) # 1 ipy = 25.4 mm/y # ipy result should be ~1000x mpy result ratio = ipy_result / mpy_result assert 999 < ratio < 1001, f"ipy/mpy ratio should be ~1000, got {ratio}" class TestPackageDataExists: """Test that data files are accessible (for packaging verification).""" def test_nrl_coefficients_exist(self): """Verify NRL coefficient CSV files exist at canonical location.""" nrl_dir = Path(__file__).parent.parent / "external" / "nrl_coefficients" required_files = [ "HY80ORRCoeffs.csv", "HY80HERCoeffs.csv", "SS316ORRCoeffs.csv", "SS316PassCoeffs.csv", "SeawaterPotentialData.xml", # Consolidated from data/nrl_csv_files/ ] for filename in required_files: filepath = nrl_dir / filename assert filepath.exists(), f"Missing required data file: {filepath}" def test_nrl_csv_files_deleted(self): """Verify the duplicate data directory was removed.""" old_dir = Path(__file__).parent.parent / "data" / "nrl_csv_files" assert not old_dir.exists(), ( f"Duplicate data directory still exists: {old_dir}. " "Should have been consolidated to external/nrl_coefficients/" ) def test_databases_init_exists(self): """Verify databases/__init__.py was created.""" init_file = Path(__file__).parent.parent / "databases" / "__init__.py" assert init_file.exists(), "databases/__init__.py is missing" class TestCodeChangesVerification: """Verify the code changes were actually made to the source files.""" def test_galvanic_k_constant_fixed_in_source(self): """Verify predict_galvanic_corrosion.py has the fixed K constant.""" source_file = Path(__file__).parent.parent / "tools" / "mechanistic" / "predict_galvanic_corrosion.py" content = source_file.read_text(encoding="utf-8") # Should contain the new K calculation assert "SECONDS_PER_YEAR" in content, "SECONDS_PER_YEAR variable not found" assert "3.27e6" not in content or "Previous value 3.27e6" in content, ( "Old buggy K value 3.27e6 still present without being documented as fixed" ) def test_ipy_conversion_fixed_in_material_screening(self): """Verify material_screening.py has fixed ipy conversion.""" source_file = Path(__file__).parent.parent / "tools" / "handbook" / "material_screening.py" content = source_file.read_text(encoding="utf-8") # Should use *= 25.4 for ipy, not /= 39.37 assert "*= 25.4" in content or "* 25.4" in content, ( "ipy *= 25.4 conversion not found in material_screening.py" ) def test_ipy_conversion_fixed_in_typical_rates(self): """Verify typical_rates.py has fixed ipy conversion.""" source_file = Path(__file__).parent.parent / "tools" / "handbook" / "typical_rates.py" content = source_file.read_text(encoding="utf-8") # Should have separate handling for ipy assert "* 25.4" in content, ( "ipy * 25.4 conversion not found in typical_rates.py" ) def test_pyproject_has_package_data(self): """Verify pyproject.toml declares package data.""" source_file = Path(__file__).parent.parent / "pyproject.toml" content = source_file.read_text(encoding="utf-8") assert "[tool.setuptools.package-data]" in content, ( "package-data section not found in pyproject.toml" ) assert "include-package-data = true" in content, ( "include-package-data not found in pyproject.toml" ) def test_manifest_in_exists(self): """Verify MANIFEST.in was created.""" manifest = Path(__file__).parent.parent / "MANIFEST.in" assert manifest.exists(), "MANIFEST.in not found" content = manifest.read_text(encoding="utf-8") assert "recursive-include external" in content, ( "MANIFEST.in should include external/ directory" ) if __name__ == "__main__": pytest.main([__file__, "-v", "--tb=short"])