improve type hint coverage, make ruff format compliant

tests/test_template.py

@@ -2,30 +2,47 @@ from pathlib import Path
 
 from symconf import Template, TOMLTemplate
 
-def test_template_fill():
+
+def test_template_fill() -> None:
     # test simple replacment
-    assert Template('f{{a}} - f{{b}}').fill({
-        'a': 1,
-        'b': 2,
-    }) == '1 - 2'
+    assert (
+        Template("f{{a}} - f{{b}}").fill(
+            {
+                "a": 1,
+                "b": 2,
+            }
+        )
+        == "1 - 2"
+    )
 
     # test nested brackets (using default pattern)
-    assert Template('{{ f{{a}} - f{{b}} }}').fill({
-        'a': 1,
-        'b': 2,
-    }) == '{{ 1 - 2 }}'
+    assert (
+        Template("{{ f{{a}} - f{{b}} }}").fill(
+            {
+                "a": 1,
+                "b": 2,
+            }
+        )
+        == "{{ 1 - 2 }}"
+    )
 
     # test tight nested brackets (requires greedy quantifier)
-    assert Template('{{f{{a}} - f{{b}}}}').fill({
-        'a': 1,
-        'b': 2,
-    }) == '{{1 - 2}}'
+    assert (
+        Template("{{f{{a}} - f{{b}}}}").fill(
+            {
+                "a": 1,
+                "b": 2,
+            }
+        )
+        == "{{1 - 2}}"
+    )
 
-def test_toml_template_fill():
+
+def test_toml_template_fill() -> None:
     test_group_dir = Path(
-        __file__, '..', 'test-config-dir/groups/test/'
+        __file__, "..", "test-config-dir/groups/test/"
     ).resolve()
 
     stacked_dict = TOMLTemplate.stack_toml(test_group_dir.iterdir())
 
-    assert stacked_dict == {'base':'aaa','concrete':'zzz'}
+    assert stacked_dict == {"base": "aaa", "concrete": "zzz"}