fixing tests

lassie/tracers/fast_marching/velocity_models.py

@@ -51,21 +51,27 @@ class VelocityModel3D(BaseModel):
 
     def model_post_init(self, __context: Any) -> None:
         grid_spacing = self.grid_spacing
+        neast = int(round(self.east_size / grid_spacing)) + 1
+        nnorth = int(round(self.north_size / grid_spacing)) + 1
+        ndepth = int(round(self.depth_size / grid_spacing)) + 1
 
-        self._east_coords = np.arange(
+        self._east_coords = np.linspace(
             self.east_bounds[0],
             self.east_bounds[1],
-            grid_spacing,
+            neast,
+            endpoint=True,
         )
-        self._north_coords = np.arange(
+        self._north_coords = np.linspace(
             self.north_bounds[0],
             self.north_bounds[1],
-            grid_spacing,
+            nnorth,
+            endpoint=True,
         )
-        self._depth_coords = np.arange(
+        self._depth_coords = np.linspace(
             self.depth_bounds[0],
             self.depth_bounds[1],
-            grid_spacing,
+            ndepth,
+            endpoint=True,
         )
 
         self._velocity_model = np.zeros(