r.null: added a test (#5214)

Author: Shreshth-Malik

raster/r.null/testsuite/test_r_null.py

@@ -0,0 +1,87 @@
+import grass.script as gs
+from grass.gunittest.case import TestCase
+from grass.gunittest.main import test
+from grass.gunittest.gmodules import SimpleModule
+
+
+class TestRNull(TestCase):
+    """Test case for r.null module"""
+
+    @classmethod
+    def setUpClass(cls):
+        """Set up a temporary region and create test raster maps"""
+        cls.use_temp_region()
+        cls.runModule("g.region", n=3, s=0, e=3, w=0, res=1)
+
+        # Create map1: categories 1, 2, 3 as rows
+        cls.runModule(
+            "r.mapcalc",
+            expression="map_basic = row()",
+            overwrite=True,
+        )
+
+        # Create map1: categories null, 2, 3 as rows
+        cls.runModule(
+            "r.mapcalc",
+            expression="map_fill_nulls = if(row() == 1, null(), if(row() == 2, 2, if(row() == 3, 3, null())))",
+            overwrite=True,
+        )
+
+        # Create map1: categories 1, 2.5, 3 as rows
+        cls.runModule(
+            "r.mapcalc",
+            expression="map2 = if(row() == 1, 1, if(row() == 2, 2.5, if(row() == 3, 3, null())))",
+            overwrite=True,
+        )
+
+    @classmethod
+    def tearDownClass(cls):
+        """Remove temporary maps and region"""
+        cls.runModule(
+            "g.remove",
+            flags="f",
+            type="raster",
+            name=["map_basic", "map_fill_nulls", "map2"],
+        )
+        cls.del_temp_region()
+
+    def test_basic(self):
+        """Verify module execute with -i flag"""
+        module = SimpleModule("r.null", map="map_basic", setnull="1", flags="i")
+        self.assertModule(module)
+
+        # Validate category mappings using r.category
+        category_output = gs.parse_command(
+            "r.describe", map="map_basic", format="json", flags="1"
+        )
+        expected_output = {"has_nulls": True, "values": [2, 3]}
+
+        self.assertEqual(category_output, expected_output)
+
+    def test_float_flag(self):
+        """Verify module execute with -f flag"""
+        module = SimpleModule("r.null", map="map2", setnull="1", flags="f")
+        self.assertModule(module)
+
+        category_output = gs.parse_command(
+            "r.describe", map="map2", format="json", flags="r"
+        )
+        expected_output = {"has_nulls": True, "ranges": [{"min": 2.5, "max": 3}]}
+
+        self.assertEqual(category_output, expected_output)
+
+    def test_fill_nulls(self):
+        """Verify module fills nulls"""
+        module = SimpleModule("r.null", map="map_fill_nulls", null="1")
+        self.assertModule(module)
+
+        category_output = gs.parse_command(
+            "r.describe", map="map_fill_nulls", format="json", flags="1"
+        )
+        expected_output = {"has_nulls": False, "values": [1, 2, 3]}
+
+        self.assertEqual(category_output, expected_output)
+
+
+if __name__ == "__main__":
+    test()