test(config): add tests

pubspec.yaml

@@ -10,6 +10,7 @@ dependencies:
 dev_dependencies:
   pedantic: ^1.11.0
   ffigen: ^3.1.0-dev.1
+  test: ^1.17.5
 
 ffigen:
   output: "lib/src/libgit2_bindings.dart"

test/config_test.dart

@@ -0,0 +1,66 @@
+import 'dart:io';
+
+import 'package:test/test.dart';
+import 'package:libgit2dart/src/util.dart';
+import 'package:libgit2dart/src/config.dart';
+
+void main() {
+  const configFileName = 'test_config';
+  group('Config', () {
+    setUpAll(() {
+      libgit2.git_libgit2_init();
+    });
+
+    setUp(() {
+      File('${Directory.current.path}/test/$configFileName').writeAsStringSync(
+          '[core]\n\trepositoryformatversion = 0\n\tbare = false\n[remote "origin"]\n\turl = someurl');
+    });
+
+    tearDown(() {
+      File('${Directory.current.path}/test/$configFileName').deleteSync();
+    });
+
+    tearDownAll(() {
+      libgit2.git_libgit2_shutdown();
+    });
+
+    test('opens file successfully', () {
+      final config = Config();
+      expect(config, isA<Config>());
+      config.close();
+    });
+
+    test('opens file successfully with provided path', () {
+      final config = Config(path: 'test/$configFileName');
+      expect(config, isA<Config>());
+      config.close();
+    });
+
+    test('gets entries of file', () {
+      final config = Config(path: 'test/$configFileName');
+      expect(config.entries['core.repositoryformatversion'], equals('0'));
+      config.close();
+    });
+
+    test('sets boolean value for provided key', () {
+      final config = Config(path: 'test/$configFileName');
+      config.setEntry('core.bare', true);
+      expect(config.entries['core.bare'], equals('true'));
+      config.close();
+    });
+
+    test('sets integer value for provided key', () {
+      final config = Config(path: 'test/$configFileName');
+      config.setEntry('core.repositoryformatversion', 1);
+      expect(config.entries['core.repositoryformatversion'], equals('1'));
+      config.close();
+    });
+
+    test('sets string value for provided key', () {
+      final config = Config(path: 'test/$configFileName');
+      config.setEntry('remote.origin.url', 'updated');
+      expect(config.entries['remote.origin.url'], equals('updated'));
+      config.close();
+    });
+  });
+}