diff --git a/raster/r.support/tests/r_support_test.py b/raster/r.support/tests/r_support_test.py
index 2ce71ab4749..23cf1ceee6b 100644
--- a/raster/r.support/tests/r_support_test.py
+++ b/raster/r.support/tests/r_support_test.py
@@ -55,3 +55,81 @@ def test_remove_semantic_label(session):
     tools.r_support(map="test", flags="b")
     info = tools.r_info(map="test", format="json").json
     assert not info.get("semantic_label")
+
+
+def test_set_metadata_fields(session):
+    """title, units, vdatum, source1/source2 and description are all stored."""
+    tools = Tools(session=session)
+    tools.r_support(
+        map="test",
+        title="My Title",
+        units="meters",
+        vdatum="WGS84",
+        source1="Source A",
+        source2="Source B",
+        description="A description",
+    )
+
+    info = tools.r_info(map="test", format="json")
+    assert info["title"] == "My Title"
+    assert info["units"] == "meters"
+    assert info["vdatum"] == "WGS84"
+    assert info["source1"] == "Source A"
+    assert info["source2"] == "Source B"
+    assert info["description"] == "A description"
+
+
+def test_append_history(session):
+    """Each history= call appends a line rather than replacing prior ones."""
+    tools = Tools(session=session)
+    tools.r_support(map="test", history="First history line")
+    tools.r_support(map="test", history="Second history line")
+
+    info = tools.r_info(map="test", format="json")
+    assert info["comments"].endswith("First history line\nSecond history line")
+
+
+def test_savehistory_and_loadhistory(session, tmp_path):
+    """savehistory writes the history to a file that loadhistory can restore
+    onto another map."""
+    tools = Tools(session=session)
+    tools.r_support(map="test", history="Line one")
+    tools.r_support(map="test", history="Line two")
+    expected = tools.r_info(map="test", format="json")["comments"]
+
+    history_file = tmp_path / "history.txt"
+    tools.r_support(map="test", savehistory=str(history_file))
+    assert history_file.read_text() == expected + "\n"
+
+    tools.r_mapcalc(expression="test2 = 2")
+    tools.r_support(map="test2", loadhistory=str(history_file))
+    info = tools.r_info(map="test2", format="json")
+    assert info["comments"] == expected
+
+
+def test_reset_null_file_clears_null_cells(session):
+    """The -n flag (re)creates the null file, here clearing the null status
+    of a cell that matches the CELL type's null sentinel on disk."""
+    tools = Tools(session=session)
+    tools.g_region(n=1, s=0, e=3, w=0, res=1)
+    tools.r_mapcalc(expression="with_null = if(col() == 2, null(), col())")
+    before = tools.r_univar(map="with_null", format="json")
+    assert before["null_cells"] == 1
+
+    tools.r_support(map="with_null", flags="n")
+    after = tools.r_univar(map="with_null", format="json")
+    assert after["null_cells"] == 0
+
+
+def test_delete_null_file_restores_null_cells(session):
+    """The -d flag removes the null file, falling back to the implicit
+    null sentinel stored in the raw cell values."""
+    tools = Tools(session=session)
+    tools.g_region(n=1, s=0, e=3, w=0, res=1)
+    tools.r_mapcalc(expression="with_null = if(col() == 2, null(), col())")
+    tools.r_support(map="with_null", flags="n")
+    assert tools.r_univar(map="with_null", format="json")["null_cells"] == 0
+
+    tools.r_support(map="with_null", flags="d")
+    after = tools.r_univar(map="with_null", format="json")
+    assert after["null_cells"] == 1