diff --git a/app/tests/test_validator.py b/app/tests/test_validator.py
new file mode 100644
index 0000000..f9873b3
--- /dev/null
+++ b/app/tests/test_validator.py
@@ -0,0 +1,167 @@
+"""Tests for schema validation."""
+
+import json
+import tempfile
+from pathlib import Path
+
+from src.confgen.validator import SchemaValidator
+
+
+class TestSchemaValidator:
+    """Tests for SchemaValidator."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        self.schema_data = {
+            "type": "object",
+            "properties": {
+                "name": {"type": "string"},
+                "port": {"type": "integer", "minimum": 1, "maximum": 65535},
+                "enabled": {"type": "boolean"},
+                "timeout": {"type": "number", "minimum": 0},
+            },
+            "required": ["name", "port"],
+        }
+
+        with tempfile.NamedTemporaryFile(
+            mode="w", suffix=".json", delete=False
+        ) as f:
+            json.dump(self.schema_data, f)
+            self.schema_path = f.name
+
+        self.validator = SchemaValidator(self.schema_path)
+
+    def teardown_method(self):
+        """Clean up test fixtures."""
+        Path(self.schema_path).unlink()
+
+    def test_validate_valid_config(self):
+        """Test validating a valid configuration."""
+        config = {"name": "myapp", "port": 8080, "enabled": True, "timeout": 30}
+
+        is_valid, errors = self.validator.validate(config)
+
+        assert is_valid is True
+        assert len(errors) == 0
+
+    def test_validate_missing_required_field(self):
+        """Test that missing required field fails validation."""
+        config = {"name": "myapp"}
+
+        is_valid, errors = self.validator.validate(config)
+
+        assert is_valid is False
+        assert len(errors) > 0
+        assert any("port" in error for error in errors)
+
+    def test_validate_invalid_type(self):
+        """Test that invalid type fails validation."""
+        config = {"name": "myapp", "port": "not_a_number"}
+
+        is_valid, errors = self.validator.validate(config)
+
+        assert is_valid is False
+        assert len(errors) > 0
+
+    def test_validate_integer_out_of_range(self):
+        """Test that integer out of range fails validation."""
+        config = {"name": "myapp", "port": 70000}
+
+        is_valid, errors = self.validator.validate(config)
+
+        assert is_valid is False
+        assert any("minimum" in error or "maximum" in error for error in errors)
+
+    def test_validate_boolean_type(self):
+        """Test validating boolean fields."""
+        config = {"name": "myapp", "port": 8080, "enabled": "not_boolean"}
+
+        is_valid, errors = self.validator.validate(config)
+
+        assert is_valid is False
+
+    def test_format_error_with_path(self):
+        """Test error formatting includes the path."""
+        schema_with_nested = {
+            "type": "object",
+            "properties": {
+                "database": {
+                    "type": "object",
+                    "properties": {
+                        "host": {"type": "string"},
+                        "port": {"type": "integer"},
+                    },
+                    "required": ["host"],
+                },
+            },
+        }
+
+        with tempfile.NamedTemporaryFile(
+            mode="w", suffix=".json", delete=False
+        ) as f:
+            json.dump(schema_with_nested, f)
+            nested_schema_path = f.name
+
+        validator = SchemaValidator(nested_schema_path)
+        config = {"database": {"port": "invalid"}}
+
+        is_valid, errors = validator.validate(config)
+
+        assert is_valid is False
+        Path(nested_schema_path).unlink()
+
+    def test_get_schema_summary(self):
+        """Test getting a summary of the schema."""
+        summary = self.validator.get_schema_summary()
+
+        assert summary["type"] == "object"
+        assert "name" in summary["required"]
+        assert "port" in summary["properties"]
+        assert "type" in summary["properties"]["name"]
+
+    def test_check_property_exists(self):
+        """Test checking if property exists in data."""
+        config = {"database": {"host": "localhost"}}
+
+        assert self.validator.check_property_exists(config, "database.host") is True
+        assert self.validator.check_property_exists(config, "database.port") is False
+        assert self.validator.check_property_exists(config, "nonexistent") is False
+
+    def test_validate_nested_object(self):
+        """Test validating nested objects."""
+        schema = {
+            "type": "object",
+            "properties": {
+                "database": {
+                    "type": "object",
+                    "properties": {
+                        "host": {"type": "string"},
+                        "port": {"type": "integer"},
+                    },
+                    "required": ["host", "port"],
+                },
+            },
+            "required": ["database"],
+        }
+
+        with tempfile.NamedTemporaryFile(
+            mode="w", suffix=".json", delete=False
+        ) as f:
+            json.dump(schema, f)
+            nested_schema_path = f.name
+
+        validator = SchemaValidator(nested_schema_path)
+        config = {"database": {"host": "localhost", "port": 5432}}
+
+        is_valid, errors = validator.validate(config)
+
+        assert is_valid is True
+        Path(nested_schema_path).unlink()
+
+    def test_validate_with_default_values(self):
+        """Test that validation ignores missing optional fields."""
+        config = {"name": "myapp", "port": 8080}
+
+        is_valid, errors = self.validator.validate(config)
+
+        assert is_valid is True