Tests for updates where nothing is updated

Co-authored-by: Daniel Roy Greenfeld <[email protected]>

tests/test_query.py

@@ -1,6 +1,8 @@
 import types
 
 
+# Basic query tests
+
 def test_query(fresh_db):
     fresh_db["dogs"].insert_all([{"name": "Cleo"}, {"name": "Pancakes"}])
     results = fresh_db.query("select * from dogs order by name desc")
@@ -15,3 +17,11 @@ def test_execute_returning_dicts(fresh_db):
     assert fresh_db.execute_returning_dicts("select * from test") == [
         {"id": 1, "bar": 2}
     ]
+
+def test_query_no_update(fresh_db):
+    """Test that a query that doesn't update the database:
+    1) Returns an empty list and 2) Doesn't change the database"""
+    fresh_db["message"].insert({"msg_type": "greeting", "content": "hello"})
+    results = fresh_db.query("update message set msg_type='note' where msg_type='md'")
+    assert list(results) == []
+    assert list(fresh_db["message"].rows) == [{"msg_type": "greeting", "content": "hello"}]

tests/test_update.py

@@ -6,14 +6,29 @@
 from sqlite_minutils.db import NotFoundError
 
 
+## Updates where nothing changes
+
+def test_update_no_change(fresh_db):
+    "Test updating a row with the same values it already has"
+    table = fresh_db["table"]
+    table.insert({"foo": "bar"})
+    table.update(1, {"foo": "bar"})
+    assert [{"foo": "bar"}] == list(table.rows)
+    table.update(1, {})
+    assert [{"foo": "bar"}] == list(table.rows)
+
+## Updates where something changes
+
 def test_update_rowid_table(fresh_db):
+    "Test updating a row that just got inserted, using the inserted row's last_pk as rowid"
     table = fresh_db["table"]
     rowid = table.insert({"foo": "bar"}).last_pk
     table.update(rowid, {"foo": "baz"})
     assert [{"foo": "baz"}] == list(table.rows)
 
 
 def test_update_pk_table(fresh_db):
+    "Like test_update_rowid_table, but with a user-specified primary key"
     table = fresh_db["table"]
     pk = table.insert({"foo": "bar", "id": 5}, pk="id").last_pk
     assert 5 == pk