add test for singleplane

tests/test_singleplane.py

@@ -0,0 +1,55 @@
+from math import pi
+
+import torch
+
+from caustics import FlatLambdaCDM, SIE, SinglePlane
+from caustics.utils import meshgrid
+
+
+def test_singleplane():
+
+    z_l = 0.5
+    z_s = 1.0
+    cosmology = FlatLambdaCDM(name="cosmo")
+    sie1 = SIE(
+        name="sie1", cosmology=cosmology, x0=0.2, y0=0.1, q=0.7, phi=pi / 3, b=1.0
+    )
+    sie2 = SIE(
+        name="sie2", cosmology=cosmology, x0=-0.2, y0=-0.3, q=0.3, phi=pi / 2, b=1.3
+    )
+
+    sp = SinglePlane(
+        name="singleplane", cosmology=cosmology, z_l=z_l, z_s=z_s, lenses=[sie1, sie2]
+    )
+
+    thx, thy = meshgrid(0.01, 10, device=torch.device("cpu"))
+
+    n_pix = 50
+    res = 0.05
+    upsample_factor = 2
+    thx, thy = meshgrid(
+        res / upsample_factor,
+        upsample_factor * n_pix,
+        upsample_factor * n_pix,
+        dtype=torch.float32,
+    )
+
+    sp_ax, sp_ay = sp.reduced_deflection_angle(thx, thy)
+    sp_p = sp.potential(thx, thy)
+    sp_c = sp.convergence(thx, thy)
+
+    assert torch.all(torch.isfinite(sp_ax))
+    assert torch.all(torch.isfinite(sp_ay))
+    assert torch.all(torch.isfinite(sp_p))
+    assert torch.all(torch.isfinite(sp_c))
+
+    check_ax, check_ay = sie1.reduced_deflection_angle(thx, thy)
+    check_ax += sie2.reduced_deflection_angle(thx, thy)[0]
+    check_ay += sie2.reduced_deflection_angle(thx, thy)[1]
+    check_p = sie1.potential(thx, thy) + sie2.potential(thx, thy)
+    check_c = sie1.convergence(thx, thy) + sie2.convergence(thx, thy)
+
+    assert torch.allclose(sp_ax, check_ax, atol=1e-5)
+    assert torch.allclose(sp_ay, check_ay, atol=1e-5)
+    assert torch.allclose(sp_p, check_p, atol=1e-5)
+    assert torch.allclose(sp_c, check_c, atol=1e-5)