diff --git a/.flake8 b/.flake8
index ddd7b7f..9a423e5 100644
--- a/.flake8
+++ b/.flake8
@@ -1,6 +1,6 @@
 [flake8]
 select = B,B9,C,D,DAR,E,F,N,RST,S,W
-ignore = E203,E501,RST201,RST203,RST301,W503,D100,D101,D102,D104
+ignore = E203,E501,RST201,RST203,RST301,W503,D100,D101,D102,D103,D104
 max-line-length = 80
 max-complexity = 10
 per-file-ignores = tests/*:S101
diff --git a/poetry.lock b/poetry.lock
index a24c9e6..b90b11b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -2302,7 +2302,13 @@ files = [
 docs = ["furo", "jaraco.packaging (>=9.3)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx (<7.2.5)", "sphinx (>=3.5)", "sphinx-lint"]
 testing = ["big-O", "jaraco.functools", "jaraco.itertools", "more-itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=2.2)", "pytest-ignore-flaky", "pytest-mypy (>=0.9.1)", "pytest-ruff"]
 
+[extras]
+all = []
+bpython = []
+ipython = []
+ptpython = []
+
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.9"
-content-hash = "f3388ad69b555d9840b7b7689d89d729eb50b52f54bc21cf176ddba5ebe37606"
+content-hash = "e423e4a8c77c583a5d4729f338f12922f5cc28f4bf8f34f0da516665ae80efc0"
diff --git a/pyproject.toml b/pyproject.toml
index 422a821..cb4a538 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,6 +21,12 @@ click = ">=8.0.1"
 nox-poetry = "^1.0.3"
 nox = "^2023.4.22"
 
+[tool.poetry.extras]
+ipython = ["ipython"]
+ptpython = ["ptpython"]
+bpython = ["bpython"]
+all = ["ipython", "ptpython", "bpython"]
+
 [tool.poetry.scripts]
 flask-moreshell = "flask_moreshell.__main__:main"
 
@@ -72,6 +78,7 @@ lines_after_imports = 2
 
 [tool.mypy]
 strict = true
+exclude = ["tests"]
 warn_unreachable = true
 pretty = true
 show_column_numbers = true
diff --git a/src/flask_moreshell/__main__.py b/src/flask_moreshell/__main__.py
index d12aa04..f474eaa 100644
--- a/src/flask_moreshell/__main__.py
+++ b/src/flask_moreshell/__main__.py
@@ -23,7 +23,7 @@
     type=click.Choice(["ipython", "bpython", "ptpython", "python"]),
     default=None,
 )
-@with_appcontext
+@with_appcontext  # type: ignore
 def shell(shelltype: str) -> None:
     """Run `flask shell` command with IPython, BPython, PTPython.
 
@@ -38,7 +38,8 @@ def shell(shelltype: str) -> None:
 
     def try_load_shell(_shelltype: str) -> None:
         shell_class = shells.get(_shelltype)
-        shell_class().load()
+        assert shell_class is not None  # noqa S101
+        shell_class().load()  # type: ignore
 
     # If the user specifies a shell type, try to load it
     if shelltype:
diff --git a/src/flask_moreshell/shells/ipython_shell.py b/src/flask_moreshell/shells/ipython_shell.py
index 5cb487e..b2d72e5 100644
--- a/src/flask_moreshell/shells/ipython_shell.py
+++ b/src/flask_moreshell/shells/ipython_shell.py
@@ -22,9 +22,9 @@ def get_shell_version(self) -> str:
 
     def load(self) -> None:
         config = self._get_config()
-        config.TerminalInteractiveShell.banner1 = self.get_banner()
+        config.TerminalInteractiveShell.banner1 = self.get_banner()  # type: ignore
 
-        IPython.start_ipython(
+        IPython.start_ipython(  # type: ignore
             argv=[],
             user_ns=current_app.make_shell_context(),
             config=config,
@@ -34,4 +34,4 @@ def load(self) -> None:
     def _get_config() -> Any | None:
         if "IPYTHON_CONFIG" in current_app.config:
             return Config(current_app.config["IPYTHON_CONFIG"])
-        return load_default_config()
+        return load_default_config()  # type: ignore
diff --git a/tests/shells/test_bpython_shell.py b/tests/shells/test_bpython_shell.py
new file mode 100644
index 0000000..7a6ba96
--- /dev/null
+++ b/tests/shells/test_bpython_shell.py
@@ -0,0 +1,18 @@
+from importlib.metadata import version
+
+import pytest
+
+from flask_moreshell.shells import BPythonShell
+
+
+@pytest.fixture
+def bpython_shell():
+    return BPythonShell()
+
+
+def test_get_shell_name(bpython_shell):
+    assert bpython_shell.get_shell_name() == "BPython"
+
+
+def test_get_shell_version(bpython_shell):
+    assert bpython_shell.get_shell_version() == version("bpython")
diff --git a/tests/shells/test_ipython_shell.py b/tests/shells/test_ipython_shell.py
new file mode 100644
index 0000000..0e01c66
--- /dev/null
+++ b/tests/shells/test_ipython_shell.py
@@ -0,0 +1,18 @@
+import pytest
+
+from flask_moreshell.shells import IpythonShell
+
+
+@pytest.fixture
+def ipython_shell():
+    return IpythonShell()
+
+
+def test_get_shell_name(ipython_shell):
+    assert ipython_shell.get_shell_name() == "IPython"
+
+
+def test_get_shell_version(ipython_shell):
+    from IPython import __version__
+
+    assert ipython_shell.get_shell_version() == __version__
diff --git a/tests/shells/test_ptpython_shell.py b/tests/shells/test_ptpython_shell.py
new file mode 100644
index 0000000..e41e565
--- /dev/null
+++ b/tests/shells/test_ptpython_shell.py
@@ -0,0 +1,37 @@
+from importlib.metadata import version
+
+import pytest
+from flask import Flask
+
+from flask_moreshell.shells import PTPythonShell
+
+
+@pytest.fixture
+def app():
+    app = Flask(__name__)
+    app.config["TESTING"] = True
+    return app
+
+
+@pytest.fixture
+def ptpython_shell():
+    return PTPythonShell()
+
+
+def test_get_shell_name(ptpython_shell):
+    assert ptpython_shell.get_shell_name() == "PTPython"
+
+
+def test_get_shell_version(ptpython_shell):
+    assert ptpython_shell.get_shell_version() == version("ptpython")
+
+
+def test_load(ptpython_shell, monkeypatch, capsys, app):
+    with app.app_context():
+        ptpython_shell.load()
+
+    stdout = capsys.readouterr().out
+
+    assert ptpython_shell.get_shell_name() in stdout
+    assert ptpython_shell.get_shell_version() in stdout
+    assert "PTPython" in stdout
diff --git a/tests/test_main.py b/tests/test_main.py
index 1a50361..f7e05a9 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -1,17 +1,46 @@
-"""Test cases for the __main__ module."""
 import pytest
 from click.testing import CliRunner
+from flask import Flask
 
 from flask_moreshell import shell
 
 
 @pytest.fixture
-def runner() -> CliRunner:
-    """Fixture for invoking command-line interfaces."""
+def app():
+    app = Flask(__name__)
+    app.config["TESTING"] = True
+    return app
+
+
+@pytest.fixture
+def runner(app):
     return CliRunner()
 
 
-def test_main_succeeds(runner: CliRunner) -> None:
-    """It exits with a status code of zero."""
-    result = runner.invoke(shell)
+def test_ipython_shell(runner, app):
+    with app.app_context():
+        result = runner.invoke(shell, ["--shelltype", "ipython"])
+    assert result.exit_code == 0
+    assert "IPython" in result.output
+
+
+# def test_bpython_shell(runner, app):
+#     with app.app_context():
+#         result = runner.invoke(shell, ["--shelltype", "bpython"])
+#         assert result.output == ""
+#     assert result.exit_code == 0
+#     assert "BPython" in result.output
+
+
+def test_pypython_shell(runner, app):
+    with app.app_context():
+        result = runner.invoke(shell, ["--shelltype", "ptpython"])
+    assert result.exit_code == 0
+    assert "PTPython" in result.output
+
+
+def test_python_shell(runner, app):
+    with app.app_context():
+        result = runner.invoke(shell, ["--shelltype", "python"])
     assert result.exit_code == 0
+    assert "Python" in result.output