Update add_grass user object for parallel build

reframe_tests/tests/test_geometry.py

@@ -8,6 +8,13 @@ from reframe_tests.tests.standard_tests import GprMaxGeometryTest, GprMaxRegress
 """
 
 
+@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 TestAddSurfaceRoughness(GprMaxGeometryTest):
     tags = {"test", "serial", "geometery", "fractal", "surface", "roughness"}
@@ -29,13 +36,6 @@ 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"}
@@ -160,6 +160,13 @@ class TestTriangleGeometry(GprMaxRegressionTest):
 """
 
 
+@rfm.simple_test
+class TestAddGrassMpi(TestAddGrass):
+    tags = {"test", "mpi", "geometery", "fractal", "surface", "grass"}
+    mpi_layout = parameter([[1, 2, 2], [3, 1, 3], [4, 1, 4]])
+    test_dependency = TestAddGrass
+
+
 @rfm.simple_test
 class TestAddSurfaceRoughnessMpi(MpiMixin, TestAddSurfaceRoughness):
     tags = {"test", "mpi", "geometery", "fractal", "surface", "roughness"}