Create tests for add_grass user object

reframe_tests/tests/src/geometry_tests/add_grass_geometry/add_grass_full.in

@@ -0,0 +1,14 @@
+#title: Heterogeneous soil using a stochastic distribution of dielectric properties given by a mixing model from Peplinski
+#domain: 0.100 0.100 0.100
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: ricker 1 1.5e9 my_ricker
+#hertzian_dipole: y 0.02 0.02 0.02 my_ricker
+#rx: 0.080 0.080 0.080
+
+#material: 8 0 1 0 half_space
+#fractal_box: 0 0 0 0.1 0.1 0.05 1.5 1 1 1 1 half_space my_fractal_box 42
+#add_grass: 0 0 0.05 0.1 0.1 0.05 1.5 0.05 0.1 100 my_fractal_box 22
+
+#geometry_objects_write: 0 0 0 0.1 0.1 0.1 full_volume

reframe_tests/tests/src/geometry_tests/add_grass_geometry/add_grass_small.in

@@ -0,0 +1,15 @@
+#title: Heterogeneous soil using a stochastic distribution of dielectric properties given by a mixing model from Peplinski
+#domain: 0.100 0.100 0.100
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: ricker 1 1.5e9 my_ricker
+#hertzian_dipole: y 0.02 0.02 0.02 my_ricker
+#rx: 0.080 0.080 0.080
+
+#material: 8 0 1 0 half_space
+#fractal_box: 0.06 0.06 0.02 0.08 0.08 0.045 1.5 1 1 1 1 half_space my_fractal_box 42
+#add_surface_roughness: 0.06 0.08 0.02 0.08 0.08 0.045 1 1 1 0.07 0.08 my_fractal_box 22
+#add_grass: 0.06 0.08 0.02 0.08 0.08 0.045 1.5 0.075 0.09 100 my_fractal_box 17
+
+#geometry_objects_write: 0 0 0 0.1 0.1 0.1 full_volume

reframe_tests/tests/test_geometry.py

@@ -29,6 +29,13 @@ class TestAddSurfaceWater(GprMaxGeometryTest):
     model = parameter(["add_surface_water_full", "add_surface_water_small"])
 
 
+@rfm.simple_test
+class TestAddGrass(GprMaxGeometryTest):
+    tags = {"test", "serial", "geometery", "fractal", "surface", "grass"}
+    sourcesdir = "src/geometry_tests/add_grass_geometry"
+    model = parameter(["add_grass_full", "add_grass_small"])
+
+
 @rfm.simple_test
 class TestBoxGeometryDefaultPml(GprMaxRegressionTest):
     tags = {"test", "serial", "geometery", "box"}