diff --git a/python/grass/app/tests/grass_app_cli_test.py b/python/grass/app/tests/grass_app_cli_test.py
index 6cbf57779a6..bf8f5628724 100644
--- a/python/grass/app/tests/grass_app_cli_test.py
+++ b/python/grass/app/tests/grass_app_cli_test.py
@@ -138,20 +138,63 @@ def test_subcommand_run_with_crs_as_pack_subprocess(pack_raster_file4x5_rows, ca
 
 
 def test_create_lock_unlock(tmp_path):
-    """Check that we can create, lock, unlock (smoke test)"""
+    """Check that locking creates the lock file and unlocking removes it"""
     project = tmp_path / "test_1"
+    lock_file = project / "PERMANENT" / ".gislock"
     assert main(["project", "create", str(project)]) == 0
+    assert not lock_file.exists()
     assert main(["mapset", "lock", str(project / "PERMANENT")]) == 0
+    assert lock_file.exists()
     assert main(["mapset", "unlock", str(project / "PERMANENT")]) == 0
+    assert not lock_file.exists()
 
 
 def test_create_mapset_lock_unlock(tmp_path):
-    """Check that we can create, lock, unlock (smoke test)"""
+    """Check that a created mapset can be locked and unlocked"""
     project = tmp_path / "test_1"
+    lock_file = project / "data_1" / ".gislock"
     assert main(["project", "create", str(project)]) == 0
     assert main(["mapset", "create", str(project / "data_1")]) == 0
     assert main(["mapset", "lock", str(project / "data_1")]) == 0
+    assert lock_file.exists()
     assert main(["mapset", "unlock", str(project / "data_1")]) == 0
+    assert not lock_file.exists()
+
+
+def test_lock_mapset_already_locked(tmp_path, capsys):
+    """Check that locking a locked mapset fails and keeps the existing lock"""
+    project = tmp_path / "test_1"
+    mapset = project / "PERMANENT"
+    assert main(["project", "create", str(project)]) == 0
+    assert main(["mapset", "lock", str(mapset)]) == 0
+    capsys.readouterr()
+    assert main(["mapset", "lock", str(mapset), "--timeout", "0"]) == 1
+    assert "currently being used by another GRASS session" in capsys.readouterr().err
+    assert (mapset / ".gislock").exists()
+
+
+def test_lock_mapset_force_remove_lock(tmp_path, capsys):
+    """Check that an existing lock can be forced to be removed and is reported"""
+    project = tmp_path / "test_1"
+    mapset = project / "PERMANENT"
+    assert main(["project", "create", str(project)]) == 0
+    assert main(["mapset", "lock", str(mapset)]) == 0
+    capsys.readouterr()
+    assert main(["mapset", "lock", str(mapset), "--force-remove-lock"]) == 0
+    assert "Removing lock in the selected mapset" in capsys.readouterr().out
+
+
+def test_lock_mapset_missing_mapset(tmp_path, capsys):
+    """Check that locking a mapset which does not exist is reported"""
+    assert main(["mapset", "lock", str(tmp_path / "missing")]) == 1
+    assert "doesn't exist" in capsys.readouterr().err
+
+
+def test_unlock_mapset_without_lock(tmp_path):
+    """Check that unlocking a mapset which is not locked is not an error"""
+    project = tmp_path / "test_1"
+    assert main(["project", "create", str(project)]) == 0
+    assert main(["mapset", "unlock", str(project / "PERMANENT")]) == 0
 
 
 def test_create_mapset(tmp_path):
@@ -239,21 +282,25 @@ def test_create_mapset(tmp_path):
     assert region["cols"] == 1
 
 
-def test_mapset_create_exists(tmp_path):
+def test_mapset_create_exists(tmp_path, capsys):
     """Check that creating mapset fails unless --overwrite is used"""
     project = tmp_path / "test_1"
     mapset = project / "data_1"
     assert main(["project", "create", str(project)]) == 0
     assert main(["mapset", "create", str(mapset)]) == 0
+    capsys.readouterr()
     assert main(["mapset", "create", str(mapset)]) == 1
+    assert "Error creating mapset" in capsys.readouterr().err
     assert main(["mapset", "create", "--overwrite", str(mapset)]) == 0
 
 
-def test_create_overwrite(tmp_path):
+def test_create_overwrite(tmp_path, capsys):
     """Check that creating when project exists fails unless overwrite is True"""
     project = tmp_path / "test_1"
     assert main(["project", "create", str(project)]) == 0
+    capsys.readouterr()
     assert main(["project", "create", str(project)]) == 1
+    assert "Error creating project" in capsys.readouterr().err
     assert main(["project", "create", "--overwrite", str(project)]) == 0
 
 
diff --git a/python/grass/script/raster.py b/python/grass/script/raster.py
index 01092ce9029..ed4033cbaf7 100644
--- a/python/grass/script/raster.py
+++ b/python/grass/script/raster.py
@@ -583,14 +583,15 @@ def deactivate(self):
             self.env["WIND_OVERRIDE"] = self._original_value
         else:
             self.env.pop("WIND_OVERRIDE", None)
-            run_command(
-                "g.remove",
-                flags="f",
-                quiet=True,
-                type="region",
-                name=self.region_name,
-                env=self.env,
-            )
+
+        run_command(
+            "g.remove",
+            flags="f",
+            quiet=True,
+            type="region",
+            name=self.region_name,
+            env=self.env,
+        )
         self._active = False
 
     def __enter__(self):
diff --git a/python/grass/script/tests/grass_script_raster_info_test.py b/python/grass/script/tests/grass_script_raster_info_test.py
new file mode 100644
index 00000000000..d44b7ecee7e
--- /dev/null
+++ b/python/grass/script/tests/grass_script_raster_info_test.py
@@ -0,0 +1,52 @@
+"""Test grass.script.raster_info"""
+
+import pytest
+
+import grass.script as gs
+
+
+def test_raster_info_extent_and_resolution_are_floats(session_2x2):
+    """Test the extent and the resolution are numbers, not text"""
+    info = gs.raster_info("ones", env=session_2x2.env)
+    assert info["north"] == pytest.approx(1.0)
+    assert info["south"] == pytest.approx(0.0)
+    assert info["east"] == pytest.approx(1.0)
+    assert info["west"] == pytest.approx(0.0)
+    assert info["nsres"] == pytest.approx(0.5)
+    assert info["ewres"] == pytest.approx(0.5)
+
+
+def test_raster_info_range_of_integer_raster(session_2x2):
+    """Test the minimum and the maximum of an integer raster are floats"""
+    info = gs.raster_info("ones", env=session_2x2.env)
+    assert info["min"] == pytest.approx(1.0)
+    assert info["max"] == pytest.approx(1.0)
+    assert isinstance(info["min"], float)
+    assert isinstance(info["max"], float)
+
+
+def test_raster_info_range_of_floating_point_raster(session_2x2):
+    """Test the minimum and the maximum of a floating point raster"""
+    gs.mapcalc("quarters = float(row()) / 4", env=session_2x2.env)
+    info = gs.raster_info("quarters", env=session_2x2.env)
+    assert info["min"] == pytest.approx(0.25)
+    assert info["max"] == pytest.approx(0.5)
+    assert info["datatype"] == "FCELL"
+
+
+def test_raster_info_range_of_raster_with_only_nulls(session_2x2):
+    """Test the minimum and the maximum are None when there are no values"""
+    gs.mapcalc("only_nulls = null()", env=session_2x2.env)
+    info = gs.raster_info("only_nulls", env=session_2x2.env)
+    assert info["min"] is None
+    assert info["max"] is None
+
+
+def test_raster_info_other_values_are_text(session_2x2):
+    """Test the values which are not converted to numbers"""
+    info = gs.raster_info("ones", env=session_2x2.env)
+    assert info["datatype"] == "CELL"
+    assert info["rows"] == "2"
+    assert info["cols"] == "2"
+    assert info["map"] == "ones"
+    assert info["mapset"] == "PERMANENT"
diff --git a/python/grass/script/tests/grass_script_raster_mask_test.py b/python/grass/script/tests/grass_script_raster_mask_test.py
index e0a66a4869e..77b6b29b4cc 100644
--- a/python/grass/script/tests/grass_script_raster_mask_test.py
+++ b/python/grass/script/tests/grass_script_raster_mask_test.py
@@ -258,3 +258,12 @@ def test_mask_manager_activate_deactivate(session_2x2):
     manager.activate()
     assert "GRASS_MASK" in session_2x2.env
     manager.deactivate()
+
+
+def test_mask_manager_restores_previous_mask_name(session_2x2):
+    """Test MaskManager restores the value of GRASS_MASK set before it started."""
+    env = session_2x2.env
+    env["GRASS_MASK"] = "previous_mask"
+    with gs.MaskManager(mask_name="temporary_mask", remove=False, env=env):
+        assert env["GRASS_MASK"] == "temporary_mask"
+    assert env["GRASS_MASK"] == "previous_mask"
diff --git a/python/grass/script/tests/grass_script_raster_region_test.py b/python/grass/script/tests/grass_script_raster_region_test.py
index ca75bc375af..3382f783965 100644
--- a/python/grass/script/tests/grass_script_raster_region_test.py
+++ b/python/grass/script/tests/grass_script_raster_region_test.py
@@ -187,3 +187,57 @@ def test_region_manager_env_save(session_2x2):
         region = gs.region(env=session_2x2.env)
         assert region["rows"] == 6
         assert region["cols"] == 6
+
+
+def test_region_manager_removes_temporary_region(session_2x2):
+    """Test RegionManager does not leave the region it saved in the mapset."""
+    env = session_2x2.env
+    with gs.RegionManager(env=env) as manager:
+        assert any(
+            name.startswith(manager.region_name)
+            for name in gs.list_strings("region", env=env)
+        )
+    assert not any(
+        name.startswith(manager.region_name)
+        for name in gs.list_strings("region", env=env)
+    )
+
+
+def test_region_manager_nested(session_2x2):
+    """Test the outer region is active again after a nested RegionManager ends."""
+    env = session_2x2.env
+    with gs.RegionManager(n=4, s=0, e=4, w=0, res=1, env=env) as outer:
+        with gs.RegionManager(n=6, s=0, e=6, w=0, res=1, env=env) as inner:
+            assert env["WIND_OVERRIDE"] == inner.region_name
+            assert gs.region(env=env)["rows"] == 6
+        assert env["WIND_OVERRIDE"] == outer.region_name
+        assert gs.region(env=env)["rows"] == 4
+    assert "WIND_OVERRIDE" not in env
+    assert gs.region(env=env)["rows"] == 2
+
+
+def test_region_manager_nested_removes_temporary_regions(session_2x2):
+    """Test a nested RegionManager does not leave its saved region in the mapset."""
+    env = session_2x2.env
+    with (
+        gs.RegionManager(env=env) as outer,
+        gs.RegionManager(env=env) as inner,
+    ):
+        pass
+    saved = gs.list_strings("region", env=env)
+    assert not any(name.startswith(outer.region_name) for name in saved)
+    assert not any(name.startswith(inner.region_name) for name in saved)
+
+
+def test_region_manager_env_nested(session_2x2):
+    """Test the outer region is active again after a nested RegionManagerEnv ends."""
+    env = session_2x2.env
+    with gs.RegionManagerEnv(n=4, s=0, e=4, w=0, res=1, env=env):
+        outer_region = env["GRASS_REGION"]
+        with gs.RegionManagerEnv(n=6, s=0, e=6, w=0, res=1, env=env):
+            assert env["GRASS_REGION"] != outer_region
+            assert gs.region(env=env)["rows"] == 6
+        assert env["GRASS_REGION"] == outer_region
+        assert gs.region(env=env)["rows"] == 4
+    assert "GRASS_REGION" not in env
+    assert gs.region(env=env)["rows"] == 2
diff --git a/python/grass/temporal/tests/grass_temporal_datetime_math_test.py b/python/grass/temporal/tests/grass_temporal_datetime_math_test.py
index 92767f47b58..2a0cf368167 100644
--- a/python/grass/temporal/tests/grass_temporal_datetime_math_test.py
+++ b/python/grass/temporal/tests/grass_temporal_datetime_math_test.py
@@ -10,6 +10,7 @@
 
 from grass.temporal.datetime_math import (
     adjust_datetime_to_granularity,
+    decrement_datetime_by_string,
     increment_datetime_by_string,
 )
 
@@ -48,6 +49,14 @@ def test_increment_datetime_by_string(start, increment, expected) -> None:
         ("2 weeks", datetime(2001, 8, 6, 0, 0)),
         ("6 months", datetime(2001, 8, 1, 0, 0)),
         ("2 years", datetime(2001, 1, 1, 0, 0)),
+        # The singular unit names work the same way.
+        ("1 second", datetime(2001, 8, 8, 12, 30, 30)),
+        ("1 minute", datetime(2001, 8, 8, 12, 30)),
+        ("1 hour", datetime(2001, 8, 8, 12, 0)),
+        ("1 day", datetime(2001, 8, 8, 0, 0)),
+        ("1 week", datetime(2001, 8, 6, 0, 0)),
+        ("1 month", datetime(2001, 8, 1, 0, 0)),
+        ("1 year", datetime(2001, 1, 1, 0, 0)),
         # With several units the finest one present wins, because truncating to
         # it already satisfies all the coarser ones.
         (
@@ -63,3 +72,49 @@ def test_adjust_datetime_to_granularity(granularity, expected) -> None:
         adjust_datetime_to_granularity(datetime(2001, 8, 8, 12, 30, 30), granularity)
         == expected
     )
+
+
+@pytest.mark.parametrize(
+    ("increment", "expected"),
+    [
+        # Each unit is accepted in singular and plural form.
+        ("1 second", datetime(2001, 1, 1, 0, 0, 1)),
+        ("9 seconds", datetime(2001, 1, 1, 0, 0, 9)),
+        ("1 minute", datetime(2001, 1, 1, 0, 1)),
+        ("7 minutes", datetime(2001, 1, 1, 0, 7)),
+        ("1 hour", datetime(2001, 1, 1, 1)),
+        ("5 hours", datetime(2001, 1, 1, 5)),
+        ("1 day", datetime(2001, 1, 2)),
+        ("2 days", datetime(2001, 1, 3)),
+        # A week is seven days, also for counts other than one.
+        ("1 week", datetime(2001, 1, 8)),
+        ("2 weeks", datetime(2001, 1, 15)),
+        ("1 month", datetime(2001, 2, 1)),
+        ("1 year", datetime(2002, 1, 1)),
+        ("3 years", datetime(2004, 1, 1)),
+    ],
+)
+def test_increment_datetime_by_string_single_unit(increment, expected) -> None:
+    assert increment_datetime_by_string(datetime(2001, 1, 1), increment) == expected
+
+
+@pytest.mark.parametrize(
+    ("decrement", "expected"),
+    [
+        ("1 second", datetime(2002, 3, 1, 12, 30, 29)),
+        ("1 minute", datetime(2002, 3, 1, 12, 29, 30)),
+        ("1 hour", datetime(2002, 3, 1, 11, 30, 30)),
+        ("1 day", datetime(2002, 2, 28, 12, 30, 30)),
+        ("2 days", datetime(2002, 2, 27, 12, 30, 30)),
+        ("1 week", datetime(2002, 2, 22, 12, 30, 30)),
+        ("2 weeks", datetime(2002, 2, 15, 12, 30, 30)),
+        ("1 month", datetime(2002, 2, 1, 12, 30, 30)),
+        # More than twelve months has to roll the year back.
+        ("13 months", datetime(2001, 2, 1, 12, 30, 30)),
+        ("1 year", datetime(2001, 3, 1, 12, 30, 30)),
+        ("3 years", datetime(1999, 3, 1, 12, 30, 30)),
+    ],
+)
+def test_decrement_datetime_by_string(decrement, expected) -> None:
+    start = datetime(2002, 3, 1, 12, 30, 30)
+    assert decrement_datetime_by_string(start, decrement) == expected
diff --git a/python/grass/temporal/tests/test_datetime_math_compute_datetime_delta_test.py b/python/grass/temporal/tests/test_datetime_math_compute_datetime_delta_test.py
index dbcbaa2830f..9aed9b119d4 100644
--- a/python/grass/temporal/tests/test_datetime_math_compute_datetime_delta_test.py
+++ b/python/grass/temporal/tests/test_datetime_math_compute_datetime_delta_test.py
@@ -1,4 +1,7 @@
 from datetime import datetime
+
+import pytest
+
 from grass.temporal.datetime_math import compute_datetime_delta, datetime_delta
 
 
@@ -287,3 +290,44 @@ def test_compute_datetime_delta_month_full() -> None:
     assert comp == datetime_delta(
         year=0, month=0, day=30, hour=0, minute=0, second=0, max_days=30
     )
+
+
+@pytest.mark.parametrize(
+    ("start", "end", "expected"),
+    [
+        # 28 hours: the hour of the end is before the one of the start.
+        (
+            datetime(2001, 1, 1, 22, 0),
+            datetime(2001, 1, 3, 2, 0),
+            datetime_delta(
+                year=0, month=0, day=1, hour=28, minute=0, second=0, max_days=1
+            ),
+        ),
+        # 26.5 hours: the minutes are counted over the hours.
+        (
+            datetime(2001, 1, 1, 10, 0),
+            datetime(2001, 1, 2, 12, 30),
+            datetime_delta(
+                year=0, month=0, day=1, hour=26, minute=1590, second=0, max_days=1
+            ),
+        ),
+        # Two days with the same minute: the minutes are counted over the days.
+        (
+            datetime(2001, 1, 1, 0, 15),
+            datetime(2001, 1, 3, 0, 15),
+            datetime_delta(
+                year=0, month=0, day=2, hour=0, minute=2880, second=0, max_days=2
+            ),
+        ),
+        # 26 hours with the same minute.
+        (
+            datetime(2001, 1, 1, 1, 15),
+            datetime(2001, 1, 2, 3, 15),
+            datetime_delta(
+                year=0, month=0, day=1, hour=26, minute=1560, second=0, max_days=1
+            ),
+        ),
+    ],
+)
+def test_compute_datetime_delta_spanning_days(start, end, expected) -> None:
+    assert compute_datetime_delta(start, end) == expected