From 092c6d61b8fd7a22818492e39eb85e187b9ab0f5 Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Wed, 6 May 2026 18:57:35 +0200
Subject: [PATCH 1/7] v.overlay: add option to remove small areas

---
 vector/v.overlay/area_area.c    | 19 ++++++++++++++-----
 vector/v.overlay/local.h        |  2 +-
 vector/v.overlay/main.c         | 16 ++++++++++++----
 vector/v.overlay/v.overlay.html | 10 +++++++++-
 vector/v.overlay/v.overlay.md   | 12 ++++++++++--
 5 files changed, 46 insertions(+), 13 deletions(-)

diff --git a/vector/v.overlay/area_area.c b/vector/v.overlay/area_area.c
index e8ae6fb3ed5..b98f249fadb 100644
--- a/vector/v.overlay/area_area.c
+++ b/vector/v.overlay/area_area.c
@@ -26,7 +26,7 @@ static int cmp_int(const void *a, const void *b)
 int area_area(struct Map_info *In, int *field, struct Map_info *Tmp,
               struct Map_info *Out, struct field_info *Fi, dbDriver *driver,
               int operator, int *ofield, ATTRIBUTES *attr, struct ilist *BList,
-              double snap)
+              double snap, double area_minsize)
 {
     int ret, input, line, nlines, area, nareas;
     int in_centr, out_cat;
@@ -172,10 +172,19 @@ int area_area(struct Map_info *In, int *field, struct Map_info *Tmp,
         Vect_remove_bridges(Tmp, NULL, NULL, NULL);
     }
 
-    G_set_verbose(0);
-    Vect_build_partial(Tmp, GV_BUILD_NONE);
-    Vect_build_partial(Tmp, GV_BUILD_BASE);
-    G_set_verbose(verbose);
+    if (area_minsize > 0) {
+        Vect_build_partial(Tmp, GV_BUILD_CENTROIDS);
+        G_message(_("Removing areas smaller than %g sqm..."), area_minsize);
+        Vect_remove_small_areas(Tmp, area_minsize, NULL, NULL);
+        Vect_build_partial(Tmp, GV_BUILD_BASE);
+    }
+    else {
+        G_set_verbose(0);
+        Vect_build_partial(Tmp, GV_BUILD_NONE);
+        Vect_build_partial(Tmp, GV_BUILD_BASE);
+        G_set_verbose(verbose);
+    }
+
     G_message(_("Merging lines..."));
     Vect_merge_lines(Tmp, GV_BOUNDARY, NULL, NULL);
 
diff --git a/vector/v.overlay/local.h b/vector/v.overlay/local.h
index 5909cb540e7..73d99faa28f 100644
--- a/vector/v.overlay/local.h
+++ b/vector/v.overlay/local.h
@@ -29,7 +29,7 @@ ATTR *find_attr(ATTRIBUTES *attributes, int cat);
 int area_area(struct Map_info *In, int *field, struct Map_info *Tmp,
               struct Map_info *Out, struct field_info *Fi, dbDriver *driver,
               int operator, int * ofield, ATTRIBUTES *attr, struct ilist *BList,
-              double snap_thresh);
+              double snap_thresh, double area_minsize);
 int line_area(struct Map_info *In, int *field, struct Map_info *Tmp,
               struct Map_info *Out, struct field_info *Fi, dbDriver *driver,
               int operator, int * ofield, ATTRIBUTES *attr,
diff --git a/vector/v.overlay/main.c b/vector/v.overlay/main.c
index 8a22730f151..ae9730027e5 100644
--- a/vector/v.overlay/main.c
+++ b/vector/v.overlay/main.c
@@ -10,7 +10,7 @@
  *               OGR support by Martin Landa <landa.martin gmail.com>
  *               Markus Metz
  * PURPOSE:
- * COPYRIGHT:    (C) 2003-2016 by the GRASS Development Team
+ * COPYRIGHT:    (C) 2003-2026 by the GRASS Development Team
  *
  *               This program is free software under the GNU General
  *               Public License (>=v2). Read the file COPYING that
@@ -36,10 +36,10 @@ int main(int argc, char *argv[])
 {
     int i, j, input, line, nlines, operator;
     int type[2], field[2], ofield[3];
-    double snap_thresh;
+    double snap_thresh, area_minsize;
     struct GModule *module;
     struct Option *in_opt[2], *out_opt, *type_opt[2], *field_opt[2],
-        *ofield_opt, *operator_opt, *snap_opt;
+        *ofield_opt, *operator_opt, *snap_opt, *minsize_opt;
     struct Flag *table_flag;
     struct Map_info In[2], Out, Tmp;
     struct line_pnts *Points, *Points2;
@@ -142,6 +142,13 @@ int main(int argc, char *argv[])
     snap_opt->type = TYPE_DOUBLE;
     snap_opt->answer = "1e-8";
 
+    minsize_opt = G_define_option();
+    minsize_opt->key = "minsize";
+    minsize_opt->label = _("Minimum size of areas to keep in square meters");
+    minsize_opt->description = _("Enable with minsize > 0");
+    minsize_opt->type = TYPE_DOUBLE;
+    minsize_opt->answer = "0";
+
     table_flag = G_define_standard_flag(G_FLG_V_TABLE);
     table_flag->guisection = _("Attributes");
 
@@ -220,6 +227,7 @@ int main(int argc, char *argv[])
                       operator_opt->answer);
 
     snap_thresh = atof(snap_opt->answer);
+    area_minsize = atof(minsize_opt->answer);
 
     Points = Vect_new_line_struct();
     Points2 = Vect_new_line_struct();
@@ -635,7 +643,7 @@ int main(int argc, char *argv[])
     /* AREA x AREA */
     if (type[0] == GV_AREA) {
         area_area(In, field, &Tmp, &Out, Fi, driver, operator, ofield, attr,
-                  BList, snap_thresh);
+                  BList, snap_thresh, area_minsize);
     }
     else { /* LINE x AREA */
         line_area(In, field, &Tmp, &Out, Fi, driver, operator, ofield, attr,
diff --git a/vector/v.overlay/v.overlay.html b/vector/v.overlay/v.overlay.html
index 7069ad58b23..90ceebb36ae 100644
--- a/vector/v.overlay/v.overlay.html
+++ b/vector/v.overlay/v.overlay.html
@@ -55,8 +55,16 @@ <h2>NOTES</h2>
 the output layer with the third number.
 
 <p>
-If <b>atype</b>=auto is given than <em>v.overlay</em> determines
+If <b>atype</b>=auto is given then <em>v.overlay</em> determines the
 feature type for <b>ainput</b> from the first found feature.
+<p>
+When overlaying two vectors with areas, very small areas can occur in the
+output. This can happen when e.g. one vector is a slightly modified
+version of the other vector (buffered or simplified). These very small
+areas can be removed by setting <b>minsize</b> to some value larger 0.
+The value is interpreted as square meters. In order to remove only noise
+from slightly mismatching boundaries, the value of <b>minsize</b> should be
+small, e.g. in the range 0.0001 to 1.
 
 <!-- This is outdated
 <p><div class="code"><pre>
diff --git a/vector/v.overlay/v.overlay.md b/vector/v.overlay/v.overlay.md
index bc5f6a670d4..db481bd7f56 100644
--- a/vector/v.overlay/v.overlay.md
+++ b/vector/v.overlay/v.overlay.md
@@ -37,8 +37,16 @@ If the *third* number of the **olayer** option is greater than 0, then
 the categories of **binput** in layer *blayer* are transferred to the
 output layer with the third number.
 
-If **atype**=auto is given than *v.overlay* determines feature type for
-**ainput** from the first found feature.
+If **atype**=auto is given then *v.overlay* determines the feature type
+for **ainput** from the first found feature.
+
+When overlaying two vectors with areas, very small areas can occur in the
+output. This can happen when e.g. one vector is a slightly modified
+version of the other vector (buffered or simplified). These very small
+areas can be removed by setting **minsize** to some value larger 0.
+The value is interpreted as square meters. In order to remove only noise
+from slightly mismatching boundaries, the value of **minsize** should be
+small, e.g. in the range 0.0001 to 1.
 
 ## EXAMPLES
 

From 1c8cca30ddfa55555acf78b6675a0ed41b03c660 Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Fri, 8 May 2026 17:24:00 +0200
Subject: [PATCH 2/7] add test

---
 vector/v.overlay/testsuite/test_v_overlay.py | 118 +++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 vector/v.overlay/testsuite/test_v_overlay.py

diff --git a/vector/v.overlay/testsuite/test_v_overlay.py b/vector/v.overlay/testsuite/test_v_overlay.py
new file mode 100644
index 00000000000..c6a4703eacc
--- /dev/null
+++ b/vector/v.overlay/testsuite/test_v_overlay.py
@@ -0,0 +1,118 @@
+import grass.script as gs
+from grass.gunittest.case import TestCase
+from grass.gunittest.main import test
+
+
+class TestVOverlay(TestCase):
+    """Test v.overlay output against expected output"""
+
+    @classmethod
+    def setUpClass(cls):
+        """Create input vectors for v.overlay."""
+        gs.run_command(
+            "v.extract",
+            input="boundary_county",
+            output="boundary_county_extract1",
+            where="NAME in ('CURRITUCK', 'COLUMBUS')",
+        )
+        gs.run_command(
+            "v.extract",
+            input="boundary_county",
+            output="boundary_county_extract2",
+            where="NAME not in ('CURRITUCK', 'COLUMBUS')",
+        )
+        # modify extract 1
+        gs.run_command(
+            "v.buffer",
+            input="boundary_county_extract1",
+            output="boundary_county_extract1_buffer_out",
+            type="area",
+            distance=2,
+        )
+        gs.run_command(
+            "v.buffer",
+            input="boundary_county_extract1_buffer_out",
+            output="boundary_county_extract1_buffer_in",
+            type="area",
+            distance=-2,
+        )
+
+    @classmethod
+    def tearDownClass(cls):
+        """Remove created vector map and temporary files, then delete the temp region."""
+        gs.run_command(
+            "g.remove", type="vector", flags="f", pattern="boundary_county_extract*"
+        )
+
+    def test_voverlay_nocleaning(self):
+        """
+        Overlay two input vectors and compare the output to the expected output.
+        The output will have many very small areas.
+        This test would fail"""
+        gs.run_command(
+            "v.overlay",
+            ainput="boundary_county_extract1_buffer_in",
+            atype="area",
+            binput="boundary_county_extract2",
+            btype="area",
+            output="boundary_county_extract_overlay_nocleaning",
+            operator="or",
+            snap=-1,
+            quiet=True,
+        )
+
+        self.assertModuleKeyValue(
+            "v.info",
+            map="boundary_county_extract_overlay_nocleaning",
+            flags="tg",
+            sep="=",
+            precision=0.1,
+            reference={
+                "nodes": 12067,
+                "primitives": 21060,
+                "points": 0,
+                "lines": 0,
+                "boundaries": 18053,
+                "centroids": 3007,
+                "areas": 6156,
+                "islands": 170,
+            },
+        )
+
+    def test_voverlay_withcleaning(self):
+        """Overlay two input vectors and compare the output to the expected output.
+        The output will have many very small areas"""
+        gs.run_command(
+            "v.overlay",
+            ainput="boundary_county_extract1_buffer_in",
+            atype="area",
+            binput="boundary_county_extract2",
+            btype="area",
+            output="boundary_county_extract_overlay_withcleaning",
+            operator="or",
+            snap=1.0e-6,
+            minsize=0.00001,
+            quiet=True,
+        )
+
+        self.assertModuleKeyValue(
+            "v.info",
+            map="boundary_county_extract_overlay_withcleaning",
+            flags="tg",
+            sep="=",
+            precision=0.1,
+            reference={
+                "nodes": 13733,
+                "primitives": 24393,
+                "points": 0,
+                "lines": 0,
+                "boundaries": 20563,
+                "centroids": 3830,
+                "areas": 6999,
+                "islands": 169,
+            },
+        )
+
+
+if __name__ == "__main__":
+    test()

From b3a781db45e181f850a0ded0fa5605bbbfa335db Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Fri, 8 May 2026 18:13:56 +0200
Subject: [PATCH 3/7] smaller test case

---
 vector/v.overlay/testsuite/test_v_overlay.py | 28 ++++++++++----------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/vector/v.overlay/testsuite/test_v_overlay.py b/vector/v.overlay/testsuite/test_v_overlay.py
index c6a4703eacc..c2b24674acb 100644
--- a/vector/v.overlay/testsuite/test_v_overlay.py
+++ b/vector/v.overlay/testsuite/test_v_overlay.py
@@ -13,13 +13,13 @@ def setUpClass(cls):
             "v.extract",
             input="boundary_county",
             output="boundary_county_extract1",
-            where="NAME in ('CURRITUCK', 'COLUMBUS')",
+            where="NAME in ('CURRITUCK')",
         )
         gs.run_command(
             "v.extract",
             input="boundary_county",
             output="boundary_county_extract2",
-            where="NAME not in ('CURRITUCK', 'COLUMBUS')",
+            where="NAME in ('CAMDEN')",
         )
         # modify extract 1
         gs.run_command(
@@ -68,14 +68,14 @@ def test_voverlay_nocleaning(self):
             sep="=",
             precision=0.1,
             reference={
-                "nodes": 12067,
-                "primitives": 21060,
+                "nodes": 1050,
+                "primitives": 1802,
                 "points": 0,
                 "lines": 0,
-                "boundaries": 18053,
-                "centroids": 3007,
-                "areas": 6156,
-                "islands": 170,
+                "boundaries": 1572,
+                "centroids": 230,
+                "areas": 529,
+                "islands": 7,
             },
         )
 
@@ -102,14 +102,14 @@ def test_voverlay_withcleaning(self):
             sep="=",
             precision=0.1,
             reference={
-                "nodes": 13733,
-                "primitives": 24393,
+                "nodes": 1232,
+                "primitives": 2164,
                 "points": 0,
                 "lines": 0,
-                "boundaries": 20563,
-                "centroids": 3830,
-                "areas": 6999,
-                "islands": 169,
+                "boundaries": 1847,
+                "centroids": 317,
+                "areas": 622,
+                "islands": 7,
             },
         )
 

From 81f77ba67ac7672c3c175bbdf62e17edb71e2a94 Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Sat, 9 May 2026 14:47:57 +0200
Subject: [PATCH 4/7] explain reason for the tests

---
 vector/v.overlay/testsuite/test_v_overlay.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/vector/v.overlay/testsuite/test_v_overlay.py b/vector/v.overlay/testsuite/test_v_overlay.py
index c2b24674acb..587faceebff 100644
--- a/vector/v.overlay/testsuite/test_v_overlay.py
+++ b/vector/v.overlay/testsuite/test_v_overlay.py
@@ -48,7 +48,9 @@ def test_voverlay_nocleaning(self):
         """
         Overlay two input vectors and compare the output to the expected output.
         The output will have many very small areas.
-        This test would fail"""
+        This test would fail in GRASS84 with a too small number of centroids.
+        Since GRASS84, calculation for centroids has been improved for
+        edge cases like very small areas."""
         gs.run_command(
             "v.overlay",
             ainput="boundary_county_extract1_buffer_in",
@@ -81,7 +83,8 @@ def test_voverlay_nocleaning(self):
 
     def test_voverlay_withcleaning(self):
         """Overlay two input vectors and compare the output to the expected output.
-        The output will have many very small areas"""
+        The output will have many very small areas.
+        This is a test for the cleaning options snap and minsize"""
         gs.run_command(
             "v.overlay",
             ainput="boundary_county_extract1_buffer_in",

From c12f2a429617049e7d719667b120c51f8dd883ee Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Wed, 13 May 2026 19:20:04 +0200
Subject: [PATCH 5/7] add pure pytest

---
 vector/v.overlay/tests/test_v_overlay.py | 128 +++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 vector/v.overlay/tests/test_v_overlay.py

diff --git a/vector/v.overlay/tests/test_v_overlay.py b/vector/v.overlay/tests/test_v_overlay.py
new file mode 100644
index 00000000000..60826b640c1
--- /dev/null
+++ b/vector/v.overlay/tests/test_v_overlay.py
@@ -0,0 +1,128 @@
+import pytest
+import grass.script as gs
+
+# run in a GRASS session with nc_spm_full_v2beta1
+
+
+class TestVOverlay:
+    """Test v.overlay output against expected output"""
+
+    # create test data
+    @pytest.fixture(scope="class", autouse=True)
+    def create_testdata(self):
+        # set up
+        gs.run_command(
+            "v.extract",
+            input="boundary_county",
+            output="boundary_county_extract1",
+            where="NAME in ('CURRITUCK')",
+        )
+        gs.run_command(
+            "v.extract",
+            input="boundary_county",
+            output="boundary_county_extract2",
+            where="NAME in ('CAMDEN')",
+        )
+        # modify extract 1
+        gs.run_command(
+            "v.buffer",
+            input="boundary_county_extract1",
+            output="boundary_county_extract1_buffer_out",
+            type="area",
+            distance=2,
+        )
+        gs.run_command(
+            "v.buffer",
+            input="boundary_county_extract1_buffer_out",
+            output="boundary_county_extract1_buffer_in",
+            type="area",
+            distance=-2,
+        )
+
+        # run the tests
+        yield
+
+        # clean up test data regardless of test success/failure
+        gs.run_command(
+            "g.remove", type="vector", flags="f", pattern="boundary_county_extract*"
+        )
+
+    def test_voverlay_nocleaning(self):
+        """
+        Overlay two input vectors and compare the output to the expected output.
+        The output will have many very small areas.
+        This test would fail in GRASS84 with a too small number of centroids.
+        Since GRASS84, calculation for centroids has been improved for
+        edge cases like very small areas."""
+        gs.run_command(
+            "v.overlay",
+            ainput="boundary_county_extract1_buffer_in",
+            atype="area",
+            binput="boundary_county_extract2",
+            btype="area",
+            output="boundary_county_extract_overlay_nocleaning",
+            operator="or",
+            snap=-1,
+            quiet=True,
+        )
+
+        reference = {
+            "nodes": 1050,
+            "primitives": 1802,
+            "points": 0,
+            "lines": 0,
+            "boundaries": 1572,
+            "centroids": 230,
+            "areas": 529,
+            "islands": 7,
+        }
+
+        observed = gs.vector_info_topo(
+            map="boundary_county_extract_overlay_nocleaning",
+        )
+
+        # compare results
+        for key in list(reference):
+            # all integers, simple comparison is ok
+            assert reference[key] == observed[key], (
+                f"Difference in {key}, expected {reference[key]}, got {observed[key]}"
+            )
+
+    def test_voverlay_withcleaning(self):
+        """Overlay two input vectors and compare the output to the expected output.
+        The output will have many very small areas.
+        This is a test for the cleaning options snap and minsize"""
+        gs.run_command(
+            "v.overlay",
+            ainput="boundary_county_extract1_buffer_in",
+            atype="area",
+            binput="boundary_county_extract2",
+            btype="area",
+            output="boundary_county_extract_overlay_withcleaning",
+            operator="or",
+            snap=1.0e-6,
+            minsize=0.00001,
+            quiet=True,
+        )
+
+        reference = {
+            "nodes": 1232,
+            "primitives": 2164,
+            "points": 0,
+            "lines": 0,
+            "boundaries": 1847,
+            "centroids": 317,
+            "areas": 622,
+            "islands": 7,
+        }
+
+        observed = gs.vector_info_topo(
+            map="boundary_county_extract_overlay_withcleaning",
+        )
+
+        # compare results
+        for key in list(reference):
+            # all integers, simple comparison is ok
+            assert reference[key] == observed[key], (
+                f"Difference in {key}, expected {reference[key]}, got {observed[key]}"
+            )

From 89a25bb4e8cc5239831189de953e63069277b5d0 Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Mon, 18 May 2026 20:25:11 +0200
Subject: [PATCH 6/7] remove unittest

---
 vector/v.overlay/testsuite/test_v_overlay.py | 121 -------------------
 1 file changed, 121 deletions(-)
 delete mode 100644 vector/v.overlay/testsuite/test_v_overlay.py

diff --git a/vector/v.overlay/testsuite/test_v_overlay.py b/vector/v.overlay/testsuite/test_v_overlay.py
deleted file mode 100644
index 587faceebff..00000000000
--- a/vector/v.overlay/testsuite/test_v_overlay.py
+++ /dev/null
@@ -1,121 +0,0 @@
-import grass.script as gs
-from grass.gunittest.case import TestCase
-from grass.gunittest.main import test
-
-
-class TestVOverlay(TestCase):
-    """Test v.overlay output against expected output"""
-
-    @classmethod
-    def setUpClass(cls):
-        """Create input vectors for v.overlay."""
-        gs.run_command(
-            "v.extract",
-            input="boundary_county",
-            output="boundary_county_extract1",
-            where="NAME in ('CURRITUCK')",
-        )
-        gs.run_command(
-            "v.extract",
-            input="boundary_county",
-            output="boundary_county_extract2",
-            where="NAME in ('CAMDEN')",
-        )
-        # modify extract 1
-        gs.run_command(
-            "v.buffer",
-            input="boundary_county_extract1",
-            output="boundary_county_extract1_buffer_out",
-            type="area",
-            distance=2,
-        )
-        gs.run_command(
-            "v.buffer",
-            input="boundary_county_extract1_buffer_out",
-            output="boundary_county_extract1_buffer_in",
-            type="area",
-            distance=-2,
-        )
-
-    @classmethod
-    def tearDownClass(cls):
-        """Remove created vector map and temporary files, then delete the temp region."""
-        gs.run_command(
-            "g.remove", type="vector", flags="f", pattern="boundary_county_extract*"
-        )
-
-    def test_voverlay_nocleaning(self):
-        """
-        Overlay two input vectors and compare the output to the expected output.
-        The output will have many very small areas.
-        This test would fail in GRASS84 with a too small number of centroids.
-        Since GRASS84, calculation for centroids has been improved for
-        edge cases like very small areas."""
-        gs.run_command(
-            "v.overlay",
-            ainput="boundary_county_extract1_buffer_in",
-            atype="area",
-            binput="boundary_county_extract2",
-            btype="area",
-            output="boundary_county_extract_overlay_nocleaning",
-            operator="or",
-            snap=-1,
-            quiet=True,
-        )
-
-        self.assertModuleKeyValue(
-            "v.info",
-            map="boundary_county_extract_overlay_nocleaning",
-            flags="tg",
-            sep="=",
-            precision=0.1,
-            reference={
-                "nodes": 1050,
-                "primitives": 1802,
-                "points": 0,
-                "lines": 0,
-                "boundaries": 1572,
-                "centroids": 230,
-                "areas": 529,
-                "islands": 7,
-            },
-        )
-
-    def test_voverlay_withcleaning(self):
-        """Overlay two input vectors and compare the output to the expected output.
-        The output will have many very small areas.
-        This is a test for the cleaning options snap and minsize"""
-        gs.run_command(
-            "v.overlay",
-            ainput="boundary_county_extract1_buffer_in",
-            atype="area",
-            binput="boundary_county_extract2",
-            btype="area",
-            output="boundary_county_extract_overlay_withcleaning",
-            operator="or",
-            snap=1.0e-6,
-            minsize=0.00001,
-            quiet=True,
-        )
-
-        self.assertModuleKeyValue(
-            "v.info",
-            map="boundary_county_extract_overlay_withcleaning",
-            flags="tg",
-            sep="=",
-            precision=0.1,
-            reference={
-                "nodes": 1232,
-                "primitives": 2164,
-                "points": 0,
-                "lines": 0,
-                "boundaries": 1847,
-                "centroids": 317,
-                "areas": 622,
-                "islands": 7,
-            },
-        )
-
-
-if __name__ == "__main__":
-    test()

From a1027b116b4ef45cd2348ae3af51159d0b0d40f2 Mon Sep 17 00:00:00 2001
From: Markus Metz <markus.metz.giswork@gmail.com>
Date: Sat, 6 Jun 2026 18:09:29 +0200
Subject: [PATCH 7/7] restore unittest, remove pytest

---
 .../{tests => testsuite}/test_v_overlay.py    | 91 +++++++++----------
 1 file changed, 42 insertions(+), 49 deletions(-)
 rename vector/v.overlay/{tests => testsuite}/test_v_overlay.py (63%)

diff --git a/vector/v.overlay/tests/test_v_overlay.py b/vector/v.overlay/testsuite/test_v_overlay.py
similarity index 63%
rename from vector/v.overlay/tests/test_v_overlay.py
rename to vector/v.overlay/testsuite/test_v_overlay.py
index 60826b640c1..587faceebff 100644
--- a/vector/v.overlay/tests/test_v_overlay.py
+++ b/vector/v.overlay/testsuite/test_v_overlay.py
@@ -1,16 +1,14 @@
-import pytest
 import grass.script as gs
+from grass.gunittest.case import TestCase
+from grass.gunittest.main import test
 
-# run in a GRASS session with nc_spm_full_v2beta1
 
-
-class TestVOverlay:
+class TestVOverlay(TestCase):
     """Test v.overlay output against expected output"""
 
-    # create test data
-    @pytest.fixture(scope="class", autouse=True)
-    def create_testdata(self):
-        # set up
+    @classmethod
+    def setUpClass(cls):
+        """Create input vectors for v.overlay."""
         gs.run_command(
             "v.extract",
             input="boundary_county",
@@ -39,10 +37,9 @@ def create_testdata(self):
             distance=-2,
         )
 
-        # run the tests
-        yield
-
-        # clean up test data regardless of test success/failure
+    @classmethod
+    def tearDownClass(cls):
+        """Remove created vector map and temporary files, then delete the temp region."""
         gs.run_command(
             "g.remove", type="vector", flags="f", pattern="boundary_county_extract*"
         )
@@ -66,28 +63,24 @@ def test_voverlay_nocleaning(self):
             quiet=True,
         )
 
-        reference = {
-            "nodes": 1050,
-            "primitives": 1802,
-            "points": 0,
-            "lines": 0,
-            "boundaries": 1572,
-            "centroids": 230,
-            "areas": 529,
-            "islands": 7,
-        }
-
-        observed = gs.vector_info_topo(
+        self.assertModuleKeyValue(
+            "v.info",
             map="boundary_county_extract_overlay_nocleaning",
+            flags="tg",
+            sep="=",
+            precision=0.1,
+            reference={
+                "nodes": 1050,
+                "primitives": 1802,
+                "points": 0,
+                "lines": 0,
+                "boundaries": 1572,
+                "centroids": 230,
+                "areas": 529,
+                "islands": 7,
+            },
         )
 
-        # compare results
-        for key in list(reference):
-            # all integers, simple comparison is ok
-            assert reference[key] == observed[key], (
-                f"Difference in {key}, expected {reference[key]}, got {observed[key]}"
-            )
-
     def test_voverlay_withcleaning(self):
         """Overlay two input vectors and compare the output to the expected output.
         The output will have many very small areas.
@@ -105,24 +98,24 @@ def test_voverlay_withcleaning(self):
             quiet=True,
         )
 
-        reference = {
-            "nodes": 1232,
-            "primitives": 2164,
-            "points": 0,
-            "lines": 0,
-            "boundaries": 1847,
-            "centroids": 317,
-            "areas": 622,
-            "islands": 7,
-        }
-
-        observed = gs.vector_info_topo(
+        self.assertModuleKeyValue(
+            "v.info",
             map="boundary_county_extract_overlay_withcleaning",
+            flags="tg",
+            sep="=",
+            precision=0.1,
+            reference={
+                "nodes": 1232,
+                "primitives": 2164,
+                "points": 0,
+                "lines": 0,
+                "boundaries": 1847,
+                "centroids": 317,
+                "areas": 622,
+                "islands": 7,
+            },
         )
 
-        # compare results
-        for key in list(reference):
-            # all integers, simple comparison is ok
-            assert reference[key] == observed[key], (
-                f"Difference in {key}, expected {reference[key]}, got {observed[key]}"
-            )
+
+if __name__ == "__main__":
+    test()