Add test for `plot_eddy_contours.py` with grid

Inst_eddies/Analysis/tests.json

@@ -34,5 +34,16 @@
 	    "$src_dir/Tests/Region_1_SHP_triplet_noise"
 	],
 	"input": "20455, 3\n"
+    },
+    {
+	"title": "Plot_eddy_contours_grid",
+	"command":
+	[
+	    "$src_dir/Inst_eddies/Analysis/plot_eddy_contours.py",
+	    "$src_dir/Overlap/Tests/Input/Region_4/Eddies_region_4", "--grid",
+	    "--save=png"
+	],
+	"description": "With grid option.",
+	"required": [["$src_dir/Inst_eddies/Tests/Input/h_region_4.nc", "h.nc"]]
     }
 ]