diff --git a/tests/test_dataforge_type_check.py b/tests/test_dataforge_type_check.py
new file mode 100644
index 0000000..62723d2
--- /dev/null
+++ b/tests/test_dataforge_type_check.py
@@ -0,0 +1,170 @@
+"""Tests for type_check module."""
+
+import pytest
+
+from dataforge.type_check import (
+    infer_type,
+    parse_type_spec,
+    check_type,
+    validate_types,
+    infer_schema_from_data,
+)
+
+
+class TestInferType:
+    """Tests for type inference."""
+
+    def test_infer_null(self):
+        assert infer_type(None) == "null"
+
+    def test_infer_boolean(self):
+        assert infer_type(True) == "boolean"
+        assert infer_type(False) == "boolean"
+
+    def test_infer_integer(self):
+        assert infer_type(42) == "integer"
+        assert infer_type(-10) == "integer"
+
+    def test_infer_float(self):
+        assert infer_type(3.14) == "number"
+        assert infer_type(0.0) == "number"
+
+    def test_infer_string(self):
+        assert infer_type("hello") == "string"
+
+    def test_infer_array(self):
+        assert infer_type([1, 2, 3]) == "array"
+
+    def test_infer_object(self):
+        assert infer_type({"key": "value"}) == "object"
+
+
+class TestParseTypeSpec:
+    """Tests for type specification parsing."""
+
+    def test_parse_string_type(self):
+        type_name, type_info = parse_type_spec("string")
+        assert type_name == "string"
+        assert type_info is None
+
+    def test_parse_object_type(self):
+        type_spec = {"type": "object", "properties": {"name": {"type": "string"}}}
+        type_name, type_info = parse_type_spec(type_spec)
+        assert type_name == "object"
+        assert type_info == type_spec
+
+
+class TestCheckType:
+    """Tests for type checking."""
+
+    def test_check_string_type_valid(self):
+        valid, error = check_type("hello", "string")
+        assert valid is True
+        assert error is None
+
+    def test_check_string_type_invalid(self):
+        valid, error = check_type(123, "string")
+        assert valid is False
+        assert "Expected string" in error
+
+    def test_check_integer_type(self):
+        valid, error = check_type(42, "integer")
+        assert valid is True
+
+    def test_check_object_type(self):
+        type_spec = {"type": "object", "properties": {"name": {"type": "string"}}}
+        valid, error = check_type({"name": "John"}, type_spec)
+        assert valid is True
+
+    def test_check_object_type_missing_property(self):
+        type_spec = {"type": "object", "properties": {"name": {"type": "string"}}, "required": ["name"]}
+        valid, error = check_type({}, type_spec)
+        assert valid is False
+        assert "Missing required property" in error
+
+    def test_check_array_type(self):
+        type_spec = {"type": "array", "items": {"type": "integer"}}
+        valid, error = check_type([1, 2, 3], type_spec)
+        assert valid is True
+
+    def test_check_array_type_invalid_item(self):
+        type_spec = {"type": "array", "items": {"type": "integer"}}
+        valid, error = check_type([1, "two", 3], type_spec)
+        assert valid is False
+        assert "Array item 1" in error
+
+    def test_check_any_type(self):
+        valid, error = check_type("anything", "any")
+        assert valid is True
+
+
+class TestValidateTypes:
+    """Tests for comprehensive type validation."""
+
+    def test_validate_valid_types(self):
+        type_spec = {"type": "object", "properties": {"name": {"type": "string"}}}
+        errors = validate_types({"name": "John"}, type_spec)
+        assert len(errors) == 0
+
+    def test_validate_invalid_types(self):
+        type_spec = {"type": "object", "properties": {"name": {"type": "string"}}}
+        errors = validate_types({"name": 123}, type_spec)
+        assert len(errors) > 0
+
+    def test_validate_nested_object(self):
+        type_spec = {
+            "type": "object",
+            "properties": {
+                "user": {
+                    "type": "object",
+                    "properties": {"name": {"type": "string"}}
+                }
+            }
+        }
+        errors = validate_types({"user": {"name": "John"}}, type_spec)
+        assert len(errors) == 0
+
+    def test_validate_required_properties(self):
+        type_spec = {
+            "type": "object",
+            "properties": {"name": {"type": "string"}},
+            "required": ["name"]
+        }
+        errors = validate_types({}, type_spec)
+        assert len(errors) > 0
+
+
+class TestInferSchemaFromData:
+    """Tests for schema inference."""
+
+    def test_infer_simple_object_schema(self):
+        data = {"name": "John", "age": 30}
+        schema = infer_schema_from_data(data)
+        assert schema["type"] == "object"
+        assert "properties" in schema
+        assert schema["properties"]["name"]["type"] == "string"
+        assert schema["properties"]["age"]["type"] == "integer"
+
+    def test_infer_nested_object_schema(self):
+        data = {"user": {"name": "John", "address": {"city": "NYC"}}}
+        schema = infer_schema_from_data(data)
+        assert schema["type"] == "object"
+        assert schema["properties"]["user"]["type"] == "object"
+        assert schema["properties"]["user"]["properties"]["address"]["type"] == "object"
+
+    def test_infer_array_schema(self):
+        data = [1, 2, 3]
+        schema = infer_schema_from_data(data)
+        assert schema["type"] == "array"
+        assert "items" in schema
+        assert schema["items"]["type"] == "integer"
+
+    def test_infer_empty_object_schema(self):
+        data = {}
+        schema = infer_schema_from_data(data)
+        assert schema["type"] == "object"
+
+    def test_infer_empty_array_schema(self):
+        data = []
+        schema = infer_schema_from_data(data)
+        assert schema["type"] == "array"