large refactor (break up ConfigManager), add more tests

tests/test_template.py

@@ -0,0 +1,31 @@
+from pathlib import Path
+
+from symconf import Template, TOMLTemplate
+
+def test_template_fill():
+    # test simple replacment
+    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 }}'
+
+    # test tight nested brackets (requires greedy quantifier)
+    assert Template('{{f{{a}} - f{{b}}}}').fill({
+        'a': 1,
+        'b': 2,
+    }) == '{{1 - 2}}'
+
+def test_toml_template_fill():
+    test_group_dir = Path(
+        __file__, '..', 'test-config-dir/groups/test/'
+    ).resolve()
+
+    stacked_dict = TOMLTemplate.stack_toml(test_group_dir.iterdir())
+
+    assert stacked_dict == {'base':'aaa','concrete':'zzz'}