diff --git a/tests/test_validators.py b/tests/test_validators.py
new file mode 100644
index 0000000..a1de5cf
--- /dev/null
+++ b/tests/test_validators.py
@@ -0,0 +1,211 @@
+"""Tests for validator modules."""
+
+import pytest
+import tempfile
+import os
+from pathlib import Path
+
+
+class TestJSONValidator:
+    """Tests for JSON validator."""
+    
+    def test_validate_valid_json(self):
+        from src.validators import JSONValidator
+        validator = JSONValidator()
+        
+        result = validator.validate('{"name": "test"}')
+        assert result.valid
+        assert result.format_type == "json"
+        assert result.data == {"name": "test"}
+    
+    def test_validate_invalid_json(self):
+        from src.validators import JSONValidator
+        validator = JSONValidator()
+        
+        result = validator.validate('{invalid json}')
+        assert not result.valid
+        assert len(result.errors) > 0
+    
+    def test_validate_empty(self):
+        from src.validators import JSONValidator
+        validator = JSONValidator()
+        
+        result = validator.validate('')
+        assert not result.valid
+    
+    def test_validate_file(self):
+        from src.validators import JSONValidator
+        validator = JSONValidator()
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            f.write('{"test": true}')
+            temp_path = f.name
+        
+        try:
+            result = validator.validate_file(temp_path)
+            assert result.valid
+        finally:
+            os.unlink(temp_path)
+
+
+class TestYAMLValidator:
+    """Tests for YAML validator."""
+    
+    def test_validate_valid_yaml(self):
+        from src.validators import YAMLValidator
+        validator = YAMLValidator()
+        
+        result = validator.validate('name: test\nvalue: 123')
+        assert result.valid
+        assert result.format_type == "yaml"
+    
+    def test_validate_invalid_yaml(self):
+        from src.validators import YAMLValidator
+        validator = YAMLValidator()
+        
+        result = validator.validate('invalid: yaml: content:')
+        assert not result.valid
+    
+    def test_validate_file(self):
+        from src.validators import YAMLValidator
+        validator = YAMLValidator()
+        
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.yaml', delete=False) as f:
+            f.write('key: value')
+            temp_path = f.name
+        
+        try:
+            result = validator.validate_file(temp_path)
+            assert result.valid
+        finally:
+            os.unlink(temp_path)
+
+
+class TestTOMLValidator:
+    """Tests for TOML validator."""
+    
+    def test_validate_valid_toml(self):
+        from src.validators import TOMLValidator
+        validator = TOMLValidator()
+        
+        result = validator.validate('name = "test"\nvalue = 123')
+        assert result.valid
+        assert result.format_type == "toml"
+    
+    def test_validate_invalid_toml(self):
+        from src.validators import TOMLValidator
+        validator = TOMLValidator()
+        
+        result = validator.validate('invalid = toml = content')
+        assert not result.valid
+
+
+class TestCSVValidator:
+    """Tests for CSV validator."""
+    
+    def test_validate_valid_csv(self):
+        from src.validators import CSVValidator
+        validator = CSVValidator()
+        
+        result = validator.validate("name,age\nAlice,30\nBob,25")
+        assert result.valid
+        assert result.format_type == "csv"
+    
+    def test_validate_empty_csv(self):
+        from src.validators import CSVValidator
+        validator = CSVValidator()
+        
+        result = validator.validate("")
+        assert not result.valid
+    
+    def test_validate_malformed_csv(self):
+        from src.validators import CSVValidator
+        validator = CSVValidator()
+        
+        result = validator.validate("name,age\nAlice")
+        assert result.valid
+        assert len(result.data) == 1
+
+
+class TestValidatorFactory:
+    """Tests for validator factory function."""
+    
+    def test_get_validator_json(self):
+        from src.validators import get_validator
+        
+        validator = get_validator("json")
+        assert validator.format_name == "json"
+    
+    def test_get_validator_yaml(self):
+        from src.validators import get_validator
+        
+        validator = get_validator("yaml")
+        assert validator.format_name == "yaml"
+    
+    def test_get_validator_toml(self):
+        from src.validators import get_validator
+        
+        validator = get_validator("toml")
+        assert validator.format_name == "toml"
+    
+    def test_get_validator_csv(self):
+        from src.validators import get_validator
+        
+        validator = get_validator("csv")
+        assert validator.format_name == "csv"
+    
+    def test_get_validator_invalid(self):
+        from src.validators import get_validator
+        
+        with pytest.raises(ValueError):
+            get_validator("invalid")
+
+
+class TestValidateData:
+    """Tests for validate_data function."""
+    
+    def test_validate_json_data(self):
+        from src.validators import validate_data
+        
+        result = validate_data('{"key": "value"}', "json")
+        assert result.valid
+    
+    def test_validate_yaml_data(self):
+        from src.validators import validate_data
+        
+        result = validate_data("key: value", "yaml")
+        assert result.valid
+
+
+class TestDetectFormat:
+    """Tests for detect_format function."""
+    
+    def test_detect_json_format(self):
+        from src.validators import detect_format
+        
+        fmt = detect_format("test.json")
+        assert fmt == "json"
+    
+    def test_detect_yaml_format(self):
+        from src.validators import detect_format
+        
+        fmt = detect_format("test.yaml")
+        assert fmt == "yaml"
+    
+    def test_detect_toml_format(self):
+        from src.validators import detect_format
+        
+        fmt = detect_format("test.toml")
+        assert fmt == "toml"
+    
+    def test_detect_csv_format(self):
+        from src.validators import detect_format
+        
+        fmt = detect_format("test.csv")
+        assert fmt == "csv"
+    
+    def test_detect_unknown_format(self):
+        from src.validators import detect_format
+        
+        fmt = detect_format("test.xyz")
+        assert fmt is None