Add non-zero test for update_magnetic

tests/updates/test_cpu_updates.py

@@ -2,6 +2,7 @@ import argparse
 
 import numpy as np
 import pytest
+from pytest import MonkeyPatch
 
 from gprMax import config, gprMax
 from gprMax.grid import FDTDGrid
@@ -11,7 +12,7 @@ from gprMax.pml import CFS
 from gprMax.updates.cpu_updates import CPUUpdates
 
 
-def build_grid(nx, ny, nz, dl=0.001, dt=3e-9):
+def build_grid(nx: int, ny: int, nz: int, dl: float = 0.001, dt: float = 3e-9) -> FDTDGrid:
     grid = FDTDGrid()
     grid.nx = nx
     grid.ny = ny
@@ -35,13 +36,13 @@ def build_grid(nx, ny, nz, dl=0.001, dt=3e-9):
 
 
 @pytest.fixture
-def config_mock(monkeypatch):
-    def _mock_simulation_config():
+def config_mock(monkeypatch: MonkeyPatch):
+    def _mock_simulation_config() -> config.SimulationConfig:
         args = argparse.Namespace(**gprMax.args_defaults)
         args.inputfile = "test.in"
         return config.SimulationConfig(args)
 
-    def _mock_model_config():
+    def _mock_model_config() -> config.ModelConfig:
         model_config = config.ModelConfig()
         model_config.ompthreads = 1
         return model_config
@@ -50,7 +51,7 @@ def config_mock(monkeypatch):
     monkeypatch.setattr(config, "get_model_config", _mock_model_config)
 
 
-def test_update_magnetic(config_mock):
+def test_update_magnetic_zero_grid(config_mock):
     grid = build_grid(100, 100, 100)
 
     expected_value = np.zeros((101, 101, 101))
@@ -72,6 +73,40 @@ def test_update_magnetic(config_mock):
         assert np.equal(pml.EPhi2, 0).all()
 
 
+def test_update_magnetic(config_mock):
+    grid = build_grid(11, 11, 11)
+
+    # Why does fields_updates_normal use i+1, j+1 and k+1 everywhere?
+    grid.updatecoeffsH[1] = 1
+
+    grid.Ex = np.tile(np.array([[[1, 2], [2, 1]], [[2, 1], [1, 2]]], dtype=np.float32), (6, 6, 6))
+    grid.Ey = np.tile(np.array([[[1, 3], [3, 1]], [[3, 1], [1, 3]]], dtype=np.float32), (6, 6, 6))
+    grid.Ez = np.tile(np.array([[[1, 4], [4, 1]], [[4, 1], [1, 4]]], dtype=np.float32), (6, 6, 6))
+    grid.Hx = np.tile(np.array([[[3, 1], [1, 3]], [[1, 3], [3, 1]]], dtype=np.float32), (6, 6, 6))
+    grid.Hy = np.tile(np.array([[[1, 5], [5, 1]], [[5, 1], [1, 5]]], dtype=np.float32), (6, 6, 6))
+    grid.Hz = np.tile(np.array([[[5, 3], [3, 5]], [[3, 5], [5, 3]]], dtype=np.float32), (6, 6, 6))
+
+    expected_Ex = grid.Ex.copy()
+    expected_Ey = grid.Ey.copy()
+    expected_Ez = grid.Ez.copy()
+    expected_Hx = grid.Hx.copy()
+    expected_Hy = grid.Hy.copy()
+    expected_Hz = grid.Hz.copy()
+    expected_Hx[1:, :-1, :-1] = np.tile(np.array([[[2]]], dtype=np.float32), (11, 11, 11))
+    expected_Hy[:-1, 1:, :-1] = np.tile(np.array([[[3]]], dtype=np.float32), (11, 11, 11))
+    expected_Hz[:-1, :-1, 1:] = np.tile(np.array([[[4]]], dtype=np.float32), (11, 11, 11))
+
+    cpu_updates = CPUUpdates(grid)
+    cpu_updates.update_magnetic()
+
+    assert np.equal(grid.Ex, expected_Ex).all()
+    assert np.equal(grid.Ey, expected_Ey).all()
+    assert np.equal(grid.Ez, expected_Ez).all()
+    assert np.equal(grid.Hx, expected_Hx).all()
+    assert np.equal(grid.Hy, expected_Hy).all()
+    assert np.equal(grid.Hz, expected_Hz).all()
+
+
 def test_update_electric_a_non_dispersive(config_mock):
     grid = build_grid(100, 100, 100)