diff --git a/algorithm/build_hash.py b/algorithm/build_hash.py
index deb21a8..1b081c3 100644
--- a/algorithm/build_hash.py
+++ b/algorithm/build_hash.py
@@ -20,6 +20,10 @@ def need_md5(func):
     """如果需要对待处理值先md5一下再操作，就加上这个装饰器"""
     @functools.wraps(func)
     def wrapper(self, value):
+        if isinstance(value, int):
+            value = str(value)
+        if isinstance(value, str):
+            value = bytes(value, encoding='utf-8')
         value = md5(value).hexdigest()
         return func(self, value)
     return wrapper
@@ -68,6 +72,8 @@ def hash_int(self, value):
         return value
 
     def hash_str(self, value):
+        if not value:
+            return 0
         res = ''
         for i in value:
             res += str(ord(i))
@@ -101,8 +107,8 @@ def __init__(self, n):
         super(SqrtMiddleHash, self).__init__(n=n)
 
     def __middle(self, value):
-        length = len(value) / 2
-        return value[length-self.n/2:length+self.n/2+1]
+        length = len(value) // 2
+        return value[length-self.n//2:length+self.n//2+1]
 
     def hash_int(self, value):
         sqrt = str(value ** 2)
diff --git a/tests/test_algorithm/test_build_hash.py b/tests/test_algorithm/test_build_hash.py
new file mode 100644
index 0000000..6d6e41e
--- /dev/null
+++ b/tests/test_algorithm/test_build_hash.py
@@ -0,0 +1,74 @@
+# -*- coding: utf-8 -*-
+# @Time    : 2018/10/8 23:20
+# @Author  : Woko
+# @File    : test_build_hash.py
+
+import random
+import string
+from hashlib import md5
+import pytest
+from algorithm import build_hash
+
+
+@pytest.fixture(scope='module')
+def str_values():
+    res = set()
+    for _ in range(100):
+        res.add(''.join(random.sample(string.printable, random.randint(0, 100))))
+    return res
+
+
+@pytest.fixture(scope='module')
+def int_values():
+    return list(range(1000))
+
+
+class RotateHashForTest(build_hash.Hash):
+    @build_hash.RotateHash()
+    def hash_int(self, value):
+        return value
+
+    @build_hash.RotateHash()
+    def hash_str(self, value):
+        return value
+
+
+@pytest.fixture(
+    params=[build_hash.DirectHash(), build_hash.ModHash(997), build_hash.SqrtMiddleHash(4),
+            build_hash.FoldHash(5), build_hash.BitHash(31, 11), RotateHashForTest()],
+    ids=['DirectHash', 'ModHash', 'SqrtMiddleHash', 'FoldHash', 'BitHash', 'RotateHash'])
+def hash_obj(request):
+    return request.param
+
+
+class TestNeedMd5(object):
+    @pytest.fixture
+    def foo(self):
+        class Foo(object):
+            @build_hash.need_md5
+            def with_md5(self, value):
+                return value
+
+        return Foo()
+
+    def test_str(self, foo, str_values):
+        for i in str_values:
+            assert foo.with_md5(i) == md5(bytes(i, encoding='utf-8')).hexdigest()
+
+    def test_int(self, foo, int_values):
+        for i in int_values:
+            assert foo.with_md5(i) == md5(str(i).encode('utf-8')).hexdigest()
+
+
+class TestHash(object):
+    def test_str(self, hash_obj, str_values):
+        str_res = set()
+        for i in str_values:
+            str_res.add(hash_obj.hash_str(i))
+        assert len(str_values) - len(str_res) < len(str_values) / 10
+
+    def test_int(self, hash_obj, int_values):
+        int_res = set()
+        for i in int_values:
+            int_res.add(hash_obj.hash_int(i))
+        assert len(int_values) - len(int_res) < len(int_values) / 10