Resolved missing ValueError in estimate_cost

scs_combined was failing with a tidy3d error due to a missing source
Added source and monkeypatch to prevent live computation

tests/test_plugins/test_design.py

@@ -168,6 +168,7 @@ def scs_combined(radius: float, num_spheres: int, tag: str) -> float:
 
     # set up simulation
     spheres = []
+    freq0 = td.C_0 / 0.5
 
     for _ in range(int(num_spheres)):
         spheres.append(
@@ -187,6 +188,13 @@ def scs_combined(radius: float, num_spheres: int, tag: str) -> float:
     sim = td.Simulation(
         size=(1, 1, 1),
         structures=spheres,
+        sources=[
+            td.PointDipole(
+                center=(0, 0, 0),
+                source_time=td.GaussianPulse(freq0=freq0, fwidth=freq0 / 10),
+                polarization="Ex",
+            )
+        ],
         grid_spec=td.GridSpec.auto(wavelength=1.0),
         run_time=1e-12,
         monitors=[mnt],
@@ -469,6 +477,11 @@ def test_estimate_cost(est_cost_func, sweep_method, monkeypatch):
     def emulated_job_delete(self):
         pass
 
+    # Still need to emulate the run as tests may call tidy3d
+    monkeypatch.setattr(web, "run", run_emulated)
+
+    monkeypatch.setattr(web.Batch, "run", emulated_batch_run)
+
     monkeypatch.setattr(web.Job, "delete", emulated_job_delete)
 
     monkeypatch.setattr(web.Job, "estimate_cost", est_cost_func)