v.what.rast: Add test file (#6109)

* v.what.rast: add test file
* fix qsort ordering by row and then col

Author: NishantBansal2003

vector/v.what.rast/local_proto.h

@@ -11,6 +11,6 @@ struct order {
 };
 
 /* search.c */
-int by_row(const void *, const void *);
+int by_row_col(const void *, const void *);
 int by_cat(const void *, const void *);
 int srch_cat(const void *, const void *);

vector/v.what.rast/main.c

@@ -304,8 +304,8 @@ int main(int argc, char *argv[])
     if (nocat_cnt)
         G_warning(_("%d points without category were skipped"), nocat_cnt);
 
-    /* Sort cache by current region row */
-    qsort(cache, point_cnt, sizeof(struct order), by_row);
+    /* Sort cache by current region row and col */
+    qsort(cache, point_cnt, sizeof(struct order), by_row_col);
 
     /* Allocate space for raster row */
     if (out_type == CELL_TYPE)

vector/v.what.rast/search.c

@@ -1,14 +1,14 @@
 #include "local_proto.h"
 
-/* for qsort, order list by row */
-int by_row(const void *ii, const void *jj)
+/* for qsort, order list by row and col */
+int by_row_col(const void *ii, const void *jj)
 {
     const struct order *i = ii, *j = jj;
 
-    if (i->row < j->row)
-        return -1;
+    if (i->row != j->row)
+        return i->row - j->row;
 
-    return (i->row > j->row);
+    return (i->col - j->col);
 }
 
 /* for qsort, order list by cat */

vector/v.what.rast/testsuite/test_v_what_rast.py

@@ -0,0 +1,115 @@
+from grass.gunittest.case import TestCase
+from grass.gunittest.main import test
+from grass.script.core import read_command
+
+
+class TestVWhatRast(TestCase):
+    """Unit tests for the v.what.rast module"""
+
+    test_raster = "test_raster"
+    float_raster = "float_raster"
+    test_vector = "test_vector"
+
+    @classmethod
+    def setUpClass(cls):
+        """Set up test environment"""
+        cls.use_temp_region()
+        cls.runModule("g.region", s=0, n=5, w=0, e=5, res=1)
+        cls.runModule(
+            "r.mapcalc",
+            expression=(f"{cls.test_raster} = if(col() < 5, col(), null())"),
+        )
+        cls.runModule(
+            "r.mapcalc",
+            expression=(f"{cls.float_raster} = if(col() < 5, col() / 2., 4.5)"),
+        )
+        cls.runModule("v.mkgrid", map=f"{cls.test_vector}", grid=[5, 5], type="point")
+
+    @classmethod
+    def tearDownClass(cls):
+        """Clean up test environment"""
+        cls.del_temp_region()
+        cls.runModule(
+            "g.remove",
+            flags="f",
+            type="raster",
+            name=[cls.test_raster, cls.float_raster],
+        )
+        cls.runModule(
+            "g.remove",
+            flags="f",
+            type="vector",
+            name=[cls.test_vector],
+        )
+
+    def test_plain_output_int(self):
+        """Verify plain text output with integer map."""
+        result = read_command(
+            "v.what.rast", map=self.test_vector, raster=self.test_raster, flags="p"
+        ).splitlines()
+        expected = [
+            "21|1",
+            "22|2",
+            "23|3",
+            "24|4",
+            "25|*",
+            "16|1",
+            "17|2",
+            "18|3",
+            "19|4",
+            "20|*",
+            "11|1",
+            "12|2",
+            "13|3",
+            "14|4",
+            "15|*",
+            "6|1",
+            "7|2",
+            "8|3",
+            "9|4",
+            "10|*",
+            "1|1",
+            "2|2",
+            "3|3",
+            "4|4",
+            "5|*",
+        ]
+        self.assertEqual(result, expected)
+
+    def test_plain_output_float(self):
+        """Verify plain text output with float map."""
+        result = read_command(
+            "v.what.rast", map=self.test_vector, raster=self.float_raster, flags="p"
+        ).splitlines()
+        expected = [
+            "21|0.5",
+            "22|1",
+            "23|1.5",
+            "24|2",
+            "25|4.5",
+            "16|0.5",
+            "17|1",
+            "18|1.5",
+            "19|2",
+            "20|4.5",
+            "11|0.5",
+            "12|1",
+            "13|1.5",
+            "14|2",
+            "15|4.5",
+            "6|0.5",
+            "7|1",
+            "8|1.5",
+            "9|2",
+            "10|4.5",
+            "1|0.5",
+            "2|1",
+            "3|1.5",
+            "4|2",
+            "5|4.5",
+        ]
+        self.assertEqual(result, expected)
+
+
+if __name__ == "__main__":
+    test()