diff --git a/confsync/tests/test_validate.py b/confsync/tests/test_validate.py
new file mode 100644
index 0000000..d4ccf79
--- /dev/null
+++ b/confsync/tests/test_validate.py
@@ -0,0 +1,174 @@
+"""Tests for configuration validation system."""
+
+import pytest
+
+from confsync.core.validator import Validator
+from confsync.models.config_models import (
+    ConfigFile,
+    ConfigCategory,
+    ValidationResult,
+    ValidationIssue,
+    Severity,
+)
+
+
+class TestValidator:
+    """Tests for the Validator class."""
+
+    def test_validate_valid_json(self):
+        """Test validating valid JSON."""
+        validator = Validator()
+
+        config = ConfigFile(
+            path="/test/settings.json",
+            name="settings.json",
+            category=ConfigCategory.EDITOR,
+            tool_name="test",
+            content='{"key": "value", "number": 42}',
+        )
+
+        result = validator.validate_file(config)
+
+        assert result.is_valid
+        assert result.validated_files == 1
+        assert len(result.issues) == 0
+
+    def test_validate_invalid_json(self):
+        """Test validating invalid JSON."""
+        validator = Validator()
+
+        config = ConfigFile(
+            path="/test/settings.json",
+            name="settings.json",
+            category=ConfigCategory.EDITOR,
+            tool_name="test",
+            content='{"key": "value",}',
+        )
+
+        result = validator.validate_file(config)
+
+        assert not result.is_valid
+        assert len(result.issues) > 0
+        assert result.issues[0].severity == Severity.ERROR
+
+    def test_validate_valid_yaml(self):
+        """Test validating valid YAML."""
+        validator = Validator()
+
+        config = ConfigFile(
+            path="/test/config.yaml",
+            name="config.yaml",
+            category=ConfigCategory.EDITOR,
+            tool_name="test",
+            content='key: value\nnumber: 42',
+        )
+
+        result = validator.validate_file(config)
+
+        assert result.is_valid
+
+    def test_validate_valid_toml(self):
+        """Test validating valid TOML."""
+        validator = Validator()
+
+        config = ConfigFile(
+            path="/test/pyproject.toml",
+            name="pyproject.toml",
+            category=ConfigCategory.EDITOR,
+            tool_name="test",
+            content='[project]\nname = "test"\nversion = "1.0.0"',
+        )
+
+        result = validator.validate_file(config)
+
+        assert result.is_valid
+
+    def test_validate_shell_script_syntax(self):
+        """Test shell script syntax validation."""
+        validator = Validator()
+
+        config = ConfigFile(
+            path="/test/.bashrc",
+            name=".bashrc",
+            category=ConfigCategory.SHELL,
+            tool_name="bash",
+            content='export PATH=$PATH:/usr/local/bin\nalias ll="ls -la"',
+        )
+
+        result = validator.validate_file(config)
+
+        assert result.is_valid
+
+
+class TestValidationManifest:
+    """Tests for manifest-level validation."""
+
+    def test_validate_manifest_multiple_files(self):
+        """Test validating multiple configuration files."""
+        validator = Validator()
+
+        configs = [
+            ConfigFile(
+                path="/test/file1.json",
+                name="file1.json",
+                category=ConfigCategory.EDITOR,
+                tool_name="test",
+                content='{"key": "value"}',
+            ),
+            ConfigFile(
+                path="/test/file2.yaml",
+                name="file2.yaml",
+                category=ConfigCategory.EDITOR,
+                tool_name="test",
+                content='key: value',
+            ),
+        ]
+
+        result = validator.validate_manifest(configs)
+
+        assert result.is_valid
+        assert result.validated_files == 2
+
+
+class TestValidationReport:
+    """Tests for validation report generation."""
+
+    def test_generate_report_no_issues(self):
+        """Test generating report with no issues."""
+        validator = Validator()
+        result = ValidationResult(is_valid=True, validated_files=5)
+
+        report = validator.generate_report(result)
+
+        assert "No issues found" in report
+        assert "VALID" in report
+
+    def test_generate_report_with_issues(self):
+        """Test generating report with issues."""
+        validator = Validator()
+        result = ValidationResult(is_valid=False, validated_files=3)
+
+        result.add_issue(ValidationIssue(
+            rule="test_error",
+            message="Test error message",
+            severity=Severity.ERROR,
+            file_path="/test/file.json",
+        ))
+
+        result.add_issue(ValidationIssue(
+            rule="test_warning",
+            message="Test warning message",
+            severity=Severity.WARNING,
+            file_path="/test/file.yaml",
+            suggestion="Fix this",
+        ))
+
+        report = validator.generate_report(result)
+
+        assert "ERRORS" in report
+        assert "WARNINGS" in report
+        assert "Test error message" in report
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])