diff --git a/.gitignore b/.gitignore
index 60ecb65..064f084 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,10 @@
 .env
 /.coverage
 /coverage.xml
+
+# Virtual environment
+/.venv/
+
+# Python cache
+__pycache__/
+*.py[cod]
diff --git a/tests/test_core/test_config_manager.py b/tests/test_core/test_config_manager.py
new file mode 100644
index 0000000..d7f7ec0
--- /dev/null
+++ b/tests/test_core/test_config_manager.py
@@ -0,0 +1,118 @@
+from pathlib import Path
+import pytest
+from terminara.core.config_manager import ConfigManager
+import platform
+
+@pytest.fixture
+def config_manager(tmp_path: Path, monkeypatch) -> ConfigManager:
+    """
+    Fixture to create a ConfigManager that uses a temporary directory for its config file.
+    """
+    # We monkeypatch the __init__ to use a temporary directory
+    # This is to isolate tests from the user's actual configuration
+    # and from each other.
+
+    def mock_init(self):
+        self.config_dir = tmp_path / "Terminara"
+        self.config_dir.mkdir(parents=True, exist_ok=True)
+        self.config_file = self.config_dir / "config.json"
+
+    monkeypatch.setattr(ConfigManager, "__init__", mock_init)
+
+    return ConfigManager()
+
+
+class TestConfigManager:
+    """Test suite for the ConfigManager class."""
+
+    # We test the real __init__ separately without the fixture
+    def test_init_creates_directory(self, monkeypatch, tmp_path: Path):
+        """Test that ConfigManager's constructor creates the config directory."""
+
+        # We patch platform.system to control which config path is used
+        monkeypatch.setattr(platform, "system", lambda: "Linux")
+        # We patch Path.home to point to our temp directory for predictability
+        monkeypatch.setattr(Path, "home", lambda: tmp_path)
+
+        expected_config_dir = tmp_path / '.local' / 'share' / "Terminara"
+        assert not expected_config_dir.exists()
+
+        # This should create the directory
+        ConfigManager()
+
+        assert expected_config_dir.exists()
+
+    def test_get_config_no_file(self, config_manager: ConfigManager):
+        """Test get_config() when the config file doesn't exist."""
+        assert config_manager.get_config() == {}
+
+    def test_get_config_empty_file(self, config_manager: ConfigManager):
+        """Test get_config() when the config file is empty and raises JSONDecodeError."""
+        config_manager.config_file.touch()
+        assert config_manager.get_config() == {}
+
+    def test_get_config_invalid_json(self, config_manager: ConfigManager):
+        """Test get_config() with an invalid JSON file."""
+        config_manager.config_file.write_text("this is not json")
+        assert config_manager.get_config() == {}
+
+    def test_save_and_get_config(self, config_manager: ConfigManager):
+        """Test saving a configuration and then retrieving it."""
+        config_data = {"hello": "world", "number": 123}
+        config_manager.save_config(config_data)
+
+        retrieved_config = config_manager.get_config()
+        assert retrieved_config == config_data
+
+    def test_get_value(self, config_manager: ConfigManager):
+        """Test retrieving a single value from the configuration."""
+        config_data = {"key1": "value1", "key2": "value2"}
+        config_manager.save_config(config_data)
+
+        assert config_manager.get_value("key1") == "value1"
+
+    def test_get_nonexistent_value(self, config_manager: ConfigManager):
+        """Test that get_value() returns None for a key that does not exist."""
+        assert config_manager.get_value("nonexistent_key") is None
+
+    def test_set_value(self, config_manager: ConfigManager):
+        """Test setting a single value in the configuration."""
+        config_manager.set_value("new_key", "new_value")
+
+        # Verify by reading the whole config
+        config = config_manager.get_config()
+        assert config.get("new_key") == "new_value"
+
+        # Verify using get_value
+        assert config_manager.get_value("new_key") == "new_value"
+
+    def test_set_value_overwrites_existing(self, config_manager: ConfigManager):
+        """Test that set_value() overwrites an existing value."""
+        config_manager.set_value("key_to_overwrite", "initial_value")
+        config_manager.set_value("key_to_overwrite", "updated_value")
+
+        assert config_manager.get_value("key_to_overwrite") == "updated_value"
+
+    def test_delete_value(self, config_manager: ConfigManager):
+        """Test removing a single value from the configuration."""
+        config_data = {"key_to_keep": "A", "key_to_delete": "B"}
+        config_manager.save_config(config_data)
+
+        config_manager.delete_value("key_to_delete")
+
+        config = config_manager.get_config()
+        assert "key_to_keep" in config
+        assert "key_to_delete" not in config
+
+    def test_delete_nonexistent_value(self, config_manager: ConfigManager):
+        """Test that deleting a nonexistent key does not raise an error."""
+        config_data = {"existing_key": "value"}
+        config_manager.save_config(config_data)
+
+        try:
+            config_manager.delete_value("nonexistent_key")
+        except Exception as e:
+            pytest.fail(f"Deleting a nonexistent key raised an exception: {e}")
+
+        # Check that the original data is untouched
+        assert config_manager.get_config() == config_data
\ No newline at end of file