Initial test for ISAtmosphere block

Author: seanmcleod

tests/atmosphere/__init__.py

@@ -0,0 +1,117 @@
+########################################################################################
+##
+##                                  TESTS FOR
+##                      'atmosphere.international_standard_atmosphere.py'
+##
+########################################################################################
+
+# IMPORTS ==============================================================================
+
+import unittest
+from pathsim_flight.atmosphere import ISAtmosphere
+
+# TESTS ================================================================================
+
+class TestISAtmosphere(unittest.TestCase):
+    """Test the ISAAtmosphere block."""
+
+    def test_standard_day_sealevel_constants(self):
+        """Test standard day sea level constants"""
+        isa = ISAtmosphere()
+        self.assertEqual(isa.StdSL_pressure, 101325)
+        self.assertEqual(isa.StdSL_speed_of_sound, 340.294)
+
+    def test_band_boundaries(self):
+        """Test custom initialization with user-specified groups."""
+        isa = ISAtmosphere()
+
+        # ISA band boundaries, base temperatures, and base pressures (from standard day) for 0-71 km altitude
+        bands = [
+            [0,     288.15, 101325.0],
+            [11000, 216.65, 22632.0],
+            [20000, 216.65, 5474.9],
+            [32000, 228.65, 868.02],
+            [47000, 270.65, 110.91],
+            [51000, 270.65, 66.939],
+            [71000, 214.65, 3.9564]
+        ]
+
+        for band_info in bands:
+            isa.inputs[0] = isa.geometric_altitude(band_info[0])    # altitude
+            isa.inputs[1] = 0               # temp deviation
+
+            isa.update(None)
+
+            print(f"Testing altitude {band_info[0]} m: pressure={isa.outputs[0]} Pa, temperature={isa.outputs[2]} K")
+
+            print(isa.outputs[0], band_info[2])
+            print(isa.outputs[2], band_info[1])
+
+            self.assertAlmostEqual(isa.outputs[0], band_info[2], places=1)  # pressure
+            self.assertAlmostEqual(isa.outputs[2], band_info[1], places=1)  # temperature
+
+    def test_input_validation(self):
+        """Test input validation."""
+        isa = ISAtmosphere()
+
+        # Altitudes out of bounds of the International Standard Atmosphere should raise IndexError
+        with self.assertRaises(IndexError):
+            isa._eval(-100)
+        with self.assertRaises(IndexError):
+            isa._eval(90000)
+
+    def test_port_labels(self):
+        """Test port label definitions."""
+        self.assertEqual(ISAtmosphere.input_port_labels["altitude"], 0)
+        self.assertEqual(ISAtmosphere.input_port_labels["temp_deviation"], 1)
+        self.assertEqual(ISAtmosphere.output_port_labels["pressure"], 0)
+        self.assertEqual(ISAtmosphere.output_port_labels["density"], 1)
+        self.assertEqual(ISAtmosphere.output_port_labels["temperature"], 2)
+        self.assertEqual(ISAtmosphere.output_port_labels["speed_of_sound"], 3)
+
+    def test_temp_deviation(self):
+        """Check that temperature deviation from standard day behaves as expected."""
+
+        altitudes = [0, 5_000, 15_000, 25_000, 35_000, 49_000, 65_000, 75_000]
+        isa = ISAtmosphere()
+
+        for altitude in altitudes:
+            # No temperature deviation (standard day)
+            isa.inputs[0] = altitude
+            isa.inputs[1] = 0
+            isa.update(None)
+            pressure_std_day = isa.outputs[0]
+            density_std_day = isa.outputs[1]
+            temperature_std_day = isa.outputs[2]
+
+            # Positive temperature deviation of +10K
+            isa.inputs[0] = altitude
+            isa.inputs[1] = 10
+            isa.update(None)
+            pressure_pos_dev = isa.outputs[0]
+            density_pos_dev = isa.outputs[1]
+            temperature_pos_dev = isa.outputs[2]
+
+            # Negative temperature deviation of -10K
+            isa.inputs[0] = altitude
+            isa.inputs[1] = -10
+            isa.update(None)
+            pressure_neg_dev = isa.outputs[0]
+            density_neg_dev = isa.outputs[1]
+            temperature_neg_dev = isa.outputs[2]
+
+            # Checks
+            self.assertAlmostEqual(temperature_pos_dev, temperature_std_day + 10)
+            self.assertAlmostEqual(temperature_neg_dev, temperature_std_day - 10)
+
+            self.assertAlmostEqual(pressure_pos_dev, pressure_std_day)
+            self.assertAlmostEqual(pressure_neg_dev, pressure_std_day)
+
+            self.assertGreater(density_std_day, density_pos_dev)
+            self.assertGreater(density_neg_dev, density_std_day)
+
+
+# RUN TESTS LOCALLY ====================================================================
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)