feat: Add tests for type info

noxfile.py

@@ -3,6 +3,7 @@
 import logging
 
 import nox  # noqa
+from nox.command import CommandFailed
 from pathlib import Path  # noqa
 import sys
 
@@ -28,7 +29,6 @@
     PY37: {"coverage": True, "pkg_specs": {"pip": ">19"}},  # , "pytest-html": "1.9.0"
 }
 
-
 # set the default activated sessions, minimal for CI
 nox.options.sessions = ["tests", "flake8"]  # , "docs", "gh_pages"
 nox.options.reuse_existing_virtualenvs = True  # this can be done using -r
@@ -98,7 +98,10 @@ def tests(session: PowerSession, coverage, pkg_specs):
     conda_prefix = Path(session.bin)
     if conda_prefix.name == "bin":
         conda_prefix = conda_prefix.parent
-    session.run2("conda list", env={"CONDA_PREFIX": str(conda_prefix), "CONDA_DEFAULT_ENV": session.get_session_id()})
+    try:
+        session.run2("conda list", env={"CONDA_PREFIX": str(conda_prefix), "CONDA_DEFAULT_ENV": session.get_session_id()})
+    except CommandFailed:
+        pass
 
     # Fail if the assumed python version is not the actual one
     session.run2("python ci_tools/check_python_version.py %s" % session.python)

setup.cfg

@@ -35,12 +35,16 @@ setup_requires =
     pytest-runner
 install_requires =
     makefun>=1.5.0
+    typing-extensions>=4.2;python_version>'3.6' and python_version<'3.10'
     # note: do not use double quotes in these, this triggers a weird bug in PyCharm in debug mode only
     funcsigs;python_version<'3.3'
     enum34;python_version<'3.4'
 tests_require =
     pytest
     pytest_cases
+    # syrupy and pyright is used for testing type correctness.
+    syrupy>2;python_version>'3.6'
+    pyright;python_version>'3.6'
     # for some reason these pytest dependencies were not declared in old versions of pytest
     six;python_version<'3.6'
     attr;python_version<'3.6'

src/decopatch/main.pyi

@@ -1,12 +1,14 @@
 from typing import Any, Callable, Optional, Protocol, TypeVar, overload
 
-from decopatch.utils_disambiguation import FirstArgDisambiguation
-from decopatch.utils_modes import SignatureInfo
-
 try:
-    from typing import ParamSpec
-except ImportError:
+    # We're importing typing_extensions version first, becouse it will
+    # detect best available implementation depending on python version.
     from typing_extensions import ParamSpec
+except ImportError:
+    from typing import ParamSpec
+
+from decopatch.utils_disambiguation import FirstArgDisambiguation
+from decopatch.utils_modes import SignatureInfo
 
 P = ParamSpec("P")
 F = TypeVar("F", bound=Callable[..., Any])

tests/pyright/__snapshots__/test_typing.ambr

@@ -0,0 +1,61 @@
+# This file is generated by [syrupy](https://github.com/tophat/syrupy),
+# do not edit manually.
+# To update - run `pytest --snapshot-update`
+# name: test_typing
+  list([
+    dict({
+      'message': '''
+        No overloads for "function_decorator" match the provided arguments
+          Argument types: (Literal[True])
+      ''',
+      'range': dict({
+        'end': dict({
+          'character': 47,
+          'line': 15,
+        }),
+        'start': dict({
+          'character': 9,
+          'line': 15,
+        }),
+      }),
+      'rule': 'reportGeneralTypeIssues',
+      'severity': 'error',
+    }),
+    dict({
+      'message': '''
+        Argument of type "Literal[2]" cannot be assigned to parameter "scope" of type "str" in function "__call__"
+          "Literal[2]" is incompatible with "str"
+      ''',
+      'range': dict({
+        'end': dict({
+          'character': 22,
+          'line': 36,
+        }),
+        'start': dict({
+          'character': 21,
+          'line': 36,
+        }),
+      }),
+      'rule': 'reportGeneralTypeIssues',
+      'severity': 'error',
+    }),
+    dict({
+      'message': '''
+        Argument of type "Literal[2]" cannot be assigned to parameter "scope" of type "str" in function "__call__"
+          "Literal[2]" is incompatible with "str"
+      ''',
+      'range': dict({
+        'end': dict({
+          'character': 34,
+          'line': 52,
+        }),
+        'start': dict({
+          'character': 33,
+          'line': 52,
+        }),
+      }),
+      'rule': 'reportGeneralTypeIssues',
+      'severity': 'error',
+    }),
+  ])
+# ---

tests/pyright/base.py

@@ -0,0 +1,35 @@
+import json
+import shutil
+import subprocess
+
+__all__ = ["run_pyright", "pyright_installed"]
+
+try:
+    pyright_bin = shutil.which("pyright")
+    pyright_installed = pyright_bin is not None
+except AttributeError:
+    # shutil.which works from python 3.3 onward
+    pyright_bin = None
+    pyright_installed = False
+
+
+def run_pyright(filename):
+    """
+    Executes pyright type checker against a file, and returns json output.
+
+    Used together with syrupy snapshot to check if typing is working as expected.
+    """
+    result = subprocess.run(
+        [pyright_bin, "--outputjson", filename],
+        capture_output=True,
+        text=True,
+    )
+    assert result.stdout, result.stderr
+    output = json.loads(result.stdout)
+
+    def format_row(data):
+        # Remove "file" from json report, it has no use here.
+        del data["file"]
+        return data
+
+    return [format_row(row) for row in output["generalDiagnostics"]]

tests/test_typing.py → tests/pyright/test_file.py

@@ -1,6 +1,7 @@
-# This is test file for typing,
-# No automatic testing is used at the moment. Just use your type checker and see if it works.
-# Pytest here is used to make sure that runtime behavir matches with type checker expecter errors.
+"""
+Tests in this file do almost nothing at runtime, but serve as a source for
+testing with pyright from test_typing.py
+"""
 from typing import Any, Callable
 
 import pytest
@@ -10,37 +11,32 @@
 
 def test_invalid_parameter():
     with pytest.raises(TypeError):
-        # Error, invalid argument
+        # Error, invalid argument.
+        # This triggers error in type checking and in runtime.
         @function_decorator(invalid_param=True)
-        def decorator_wint_invalid_param(fn=DECORATED):
+        def decorator_with_invalid_param(fn=DECORATED):
             return fn
 
 
 def test_normal_decorator():
     @function_decorator
     def decorator(scope="test", fn=DECORATED):  # type: (str, Any) -> Callable[..., Any]
-        assert isinstance(scope, str)
         return fn
 
     # Ok
     @decorator
     def decorated_flat():
         pass
 
-    assert decorated_flat
-
-    with pytest.raises(AssertionError):
-        # Error, Literal[2] is incompatible with str
-        @decorator(scope=2)
-        def decorated_with_invalid_options():
-            pass
-
     # Ok, should reveal correct type for `scope`
     @decorator(scope="success")
     def decorated_with_valid_options():
         pass
 
-    assert decorated_with_valid_options
+    # Error, Literal[2] is incompatible with str
+    @decorator(scope=2)
+    def decorated_with_invalid_options():
+        pass
 
 
 def test_function_decorator_with_params():
@@ -54,4 +50,6 @@ def decorator_with_params(scope = "test", fn=DECORATED):  # type: (str, Any) ->
     def decorated_with_valid_options():
         pass
 
-    assert decorated_with_valid_options
+    @decorator_with_params(scope=2)
+    def decorated_with_invalid_options():
+        pass

tests/pyright/test_typing.py

@@ -0,0 +1,19 @@
+import sys
+
+import pytest
+
+from .base import run_pyright, pyright_installed
+
+
+@pytest.mark.skipif(
+    sys.version_info < (3, 7),
+    reason="Requires Python 3.7+",
+)
+@pytest.mark.skipif(
+    not pyright_installed,
+    reason="Pyright not installed",
+)
+def test_typing(snapshot):
+    """Test that pyright detects the typing issues on `test_file` correctly."""
+    actual = run_pyright("tests/pyright/test_file.py")
+    assert actual == snapshot