diff --git a/code/newsletter/N11/tests/conftest.py b/code/newsletter/N11/tests/conftest.py
new file mode 100644
index 0000000..ec884cb
--- /dev/null
+++ b/code/newsletter/N11/tests/conftest.py
@@ -0,0 +1,79 @@
+import dataclasses
+
+import pytest
+
+
+@dataclasses.dataclass
+class Connection:
+    def execute(self, sql: str):
+        print(f"execute {sql}...")
+        return True
+
+    def close(self):
+        print(f"\ndisconnect {repr(self)} object...")
+
+
+@dataclasses.dataclass
+class Database:
+    dialect: str = "sqlite"
+
+    def connect(self):
+        return Connection()
+
+    def close(self):
+        print(f"\ndisconnect {repr(self)} object...")
+
+
+@pytest.fixture()
+def sqlite():
+    db = Database()
+    conn = db.connect()
+    try:
+        yield conn
+    finally:
+        conn.close()
+        db.close()
+
+
+@pytest.fixture()
+def mysql():
+    db = Database(dialect="mysql")
+    conn = db.connect()
+    try:
+        yield conn
+    finally:
+        conn.close()
+        db.close()
+
+
+@pytest.fixture(params=["sqlite", "mysql"])
+def database(request):
+    db = Database(dialect=request.param)
+    conn = db.connect()
+    try:
+        yield conn
+    finally:
+        conn.close()
+        db.close()
+
+
+@pytest.fixture()
+def gender():
+    return ["male", "female"]
+
+
+@pytest.fixture()
+def cpu():
+    return "cpu"
+
+
+@pytest.fixture()
+def device(cpu):
+    return f"the device with {cpu}"
+
+
+@pytest.fixture(scope="class")
+def logger():
+    print("\nstart recording...")
+    yield
+    print("\nend recording...")
diff --git a/code/newsletter/N11/tests/pytest_setup_teardown.py b/code/newsletter/N11/tests/pytest_setup_teardown.py
new file mode 100644
index 0000000..ccc65cf
--- /dev/null
+++ b/code/newsletter/N11/tests/pytest_setup_teardown.py
@@ -0,0 +1,37 @@
+import pytest
+
+
+def setup_module():
+    print("[module level]: setup")
+
+
+def teardown_module():
+    print("[module level]: teardown")
+
+
+class TestFoo:
+    def setup(self, method) -> None:
+        print("\t\t[function level]: setup")
+
+    def teardown(self, method) -> None:
+        print("\t\t[function level]: teardown")
+
+    @classmethod
+    def setup_class(cls):
+        print("\t[class level]: setup")
+
+    @classmethod
+    def teardown_class(cls):
+        print("\t[class level]: teardown")
+
+    def test_case1(self):
+        print("\t\t\t--> test case 1 here")
+        assert True
+
+    def test_case2(self):
+        print("\t\t\t--> test case 2 here")
+        assert True
+
+
+if __name__ == '__main__':
+    pytest.main([__file__, "-s", "--no-header"])
diff --git a/code/newsletter/N11/tests/test_accumulate.py b/code/newsletter/N11/tests/test_accumulate.py
new file mode 100644
index 0000000..07e6e93
--- /dev/null
+++ b/code/newsletter/N11/tests/test_accumulate.py
@@ -0,0 +1,27 @@
+from typing import Tuple, TypeVar
+
+import pytest
+
+Number = TypeVar("Number", int, float)
+
+
+def accumulate(*numbers: Tuple[Number]) -> Number:
+    result = 0
+    for n in numbers:
+        if not isinstance(n, (int, float)):
+            raise ValueError(f"{n} isn't a valid number value")
+
+        result += n
+
+    return result
+
+
+def test_accumulate():
+    numbers = [1, 2, 3, 4]
+    expected = 10
+
+    assert accumulate(*numbers) == expected
+
+
+if __name__== '__main__':
+    pytest.main()
diff --git a/code/newsletter/N11/tests/test_accumulate_with_other_mark.py b/code/newsletter/N11/tests/test_accumulate_with_other_mark.py
new file mode 100644
index 0000000..81abd5b
--- /dev/null
+++ b/code/newsletter/N11/tests/test_accumulate_with_other_mark.py
@@ -0,0 +1,52 @@
+import sys
+from typing import Tuple, TypeVar
+
+import pytest
+
+Number = TypeVar("Number", int, float)
+VERSION = "0.0.2"
+
+
+def accumulate(*numbers: Tuple[Number]) -> Number:
+    result = 0
+    for n in numbers:
+        if not isinstance(n, (int, float)):
+            raise ValueError(f"{n} isn't a valid number value")
+
+        result += n
+
+    return result
+
+
+@pytest.mark.xfail()
+@pytest.mark.parametrize("numbers, expected", argvalues=[([10, 11, -11, -12], 1)])
+def test_accumulate_with_failed(numbers, expected):
+    assert accumulate(*numbers) == expected
+
+
+@pytest.mark.parametrize(
+    "numbers, expected",
+    argvalues=[
+        pytest.param(
+            [10, 11, -11, -12], 1, marks=pytest.mark.xfail(reason="expected failed")
+        )
+    ],
+)
+def test_accumulate_with_failed_mark(numbers, expected):
+    assert accumulate(*numbers) == expected
+
+
+@pytest.mark.skip(reason="the case is WIP")
+def test_wip_with_skip_mark():
+    ...
+
+
+def test_wip_with_skip_function():
+    if VERSION <= '0.0.2':
+        pytest.skip("the API is still on WIP")
+    assert False
+
+
+@pytest.mark.skipif(sys.platform != "linux", reason="only for linux")
+def test_wip_function_only_for_linux():
+    assert True
diff --git a/code/newsletter/N11/tests/test_accumulate_with_parametrize_mark.py b/code/newsletter/N11/tests/test_accumulate_with_parametrize_mark.py
new file mode 100644
index 0000000..c2b63d2
--- /dev/null
+++ b/code/newsletter/N11/tests/test_accumulate_with_parametrize_mark.py
@@ -0,0 +1,56 @@
+from typing import Tuple, TypeVar
+
+import pytest
+
+Number = TypeVar("Number", int, float)
+
+
+def accumulate(*numbers: Tuple[Number]) -> Number:
+    result = 0
+    for n in numbers:
+        if not isinstance(n, (int, float)):
+            raise ValueError(f"{n} isn't a valid number value")
+
+        result += n
+
+    return result
+
+
+def test_accumulate_without_mark():
+    numbers = [
+        [1, 2, 3, 4],
+        [5, 6, 7, 8],
+        [-1, 0, 1, 0],
+        [10, 11, -11, -12],
+    ]
+    expected = (10, 26, 0, 1)
+
+    for number, expect in zip(numbers, expected):
+        assert accumulate(*number) == expect
+
+
+@pytest.mark.parametrize(
+    argnames="numbers,expected",
+    argvalues=[
+        ([1, 2, 3, 4], 10),
+        ([5, 6, 7, 8], 26),
+        ([-1, 0, 1, 0], 0),
+        ([10, 11, -11, -12], 1),
+    ],
+    ids=list("abcd"),
+)
+def test_accumulate_with_parametrize_mark(numbers, expected):
+    assert accumulate(*numbers) == expected
+
+
+@pytest.mark.parametrize(argnames="even_number", argvalues=[2, 4])
+@pytest.mark.parametrize(argnames="odd_number", argvalues=[1, 3])
+def test_accumulate_with_multiple_parametrize_mark(even_number, odd_number):
+    expected = {
+        "1+2": 3,
+        "1+4": 5,
+        "3+2": 5,
+        "3+4": 7,
+    }
+    expr = f"{odd_number}+{even_number}"
+    assert accumulate(odd_number, even_number) == expected[expr]
diff --git a/code/newsletter/N11/tests/test_with_fixture.py b/code/newsletter/N11/tests/test_with_fixture.py
new file mode 100644
index 0000000..c2d1ede
--- /dev/null
+++ b/code/newsletter/N11/tests/test_with_fixture.py
@@ -0,0 +1,68 @@
+def test_sql_with_mock_sqlite_database(sqlite):
+    ok = sqlite.execute("SELECT 1;")
+    assert ok
+
+
+def test_sql_with_mock_mysql_database(mysql):
+    ok = mysql.execute("SELECT * FROM mock_table;")
+    assert ok
+
+
+def test_gender_fixture(gender):
+    print(f"Gender fixture value: {gender}")
+    assert ["male", "female"] == gender
+
+
+class TestClassScopeFixture:
+    def test_foo(self, logger):
+        assert True
+
+    def test_bar(self, logger):
+        assert True
+
+
+class TestClassScopeFixture2:
+    def test_foo2(self, logger):
+        assert True
+
+    def test_bar2(self, logger):
+        assert True
+
+
+def test_with_mock_database(database):
+    sql = "SELECT * FROM mock_table;"
+    ok = database.execute(sql)
+    assert ok
+
+
+def test_with_request_fixture(request):
+    from pprint import pformat
+
+    props = [prop for prop in dir(request) if not prop.startswith("_")]
+
+    print(f"request properties:\n{pformat(props)}")
+    assert True
+
+
+def test_with_capsys_fixture(capsys):
+    def greet(name: str = ""):
+        msg = name or "World"
+        print(f"Hello, {msg}")
+
+    greet()
+    captured = capsys.readouterr()
+    assert captured.out == "Hello, World\n"
+
+    greet("100gle")
+    captured = capsys.readouterr()
+    assert captured.out == "Hello, 100gle\n"
+
+
+def test_with_tmp_path_fixture(tmp_path):
+    import pathlib
+
+    p = tmp_path.joinpath("foo")
+    print(f"\n{p}")
+
+    assert isinstance(p, pathlib.Path)
+    assert p.stem == "foo"
diff --git a/code/newsletter/N11/tests/unittest_setup_teardown.py b/code/newsletter/N11/tests/unittest_setup_teardown.py
new file mode 100644
index 0000000..0fa3b50
--- /dev/null
+++ b/code/newsletter/N11/tests/unittest_setup_teardown.py
@@ -0,0 +1,37 @@
+import unittest
+
+
+def setUpModule():
+    print("[module level]: setup")
+
+
+def tearDownModule():
+    print("[module level]: teardown")
+
+
+class TestFoo(unittest.TestCase):
+    def setUp(self) -> None:
+        print("\t\t[function level]: setup")
+
+    def tearDown(self) -> None:
+        print("\t\t[function level]: teardown")
+
+    @classmethod
+    def setUpClass(cls):
+        print("\t[class level]: setup")
+
+    @classmethod
+    def tearDownClass(cls):
+        print("\t[class level]: teardown")
+
+    def test_case1(self):
+        print("\t\t\t--> test case 1 here")
+        self.assertEqual(1, 1)
+
+    def test_case2(self):
+        print("\t\t\t--> test case 2 here")
+        self.assertEqual(1, 1)
+
+
+if __name__ == '__main__':
+    unittest.main()