add more e2e type check tests

Author: Otto-AA

e2e_projects/type_checking/pyproject.toml

@@ -14,16 +14,21 @@ build-backend = "uv_build"
 [dependency-groups]
 dev = [
     "pyrefly>=0.52.0",
+    "pyright>=1.1.408",
     "pytest>=8.2.0",
 ]
 
 [tool.mutmut]
 debug = true
 # TODO: pyrefly ignores mutants/ dir if it is in .gitignore
-type_check_command = ["pyrefly", "check", "--output-format=json", "--use-ignore-files=false"]
+# type_check_command = ["pyrefly", "check", "--output-format=json", "--use-ignore-files=false"]
+type_check_command = ["pyright", "--outputjson"]
 
 [tool.pyrefly]
 project-includes = [
     "**/*.py*",
     "**/*.ipynb",
 ]
+
+[tool.pyright]
+typeCheckingMode = "strict"

e2e_projects/type_checking/src/type_checking/__init__.py

@@ -1,3 +1,23 @@
 def hello() -> str:
     greeting: str = "Hello from type-checking!"
     return greeting
+
+def a_hello_wrapper() -> str:
+    # verify that hello() keeps the return type str
+    # (if not, this will type error and not be mutated)
+    return hello() + "2"
+
+class Person:
+    def set_name(self, name: str):
+        self.name = name
+
+    def get_name(self):
+        # return type should be inferred as "str"
+        return self.name
+
+def mutate_me():
+    p = Person()
+    p.set_name('charlie')
+    # Verify that p.get_name keeps the return type str
+    name: str = p.get_name()
+    return name

e2e_projects/type_checking/tests/test_type_checking.py

@@ -1,4 +1,10 @@
-from type_checking import hello
+from type_checking import *
 
 def test_hello():
-    assert hello() == "Hello from type-checking!"
+    assert hello() == "Hello from type-checking!"
+
+def test_a_hello_wrapper():
+    assert isinstance(a_hello_wrapper(), str)
+
+def test_mutate_me():
+    assert mutate_me() == "charlie"

e2e_projects/type_checking/uv.lock

@@ -55,6 +55,7 @@ source-include = ["HISTORY.rst"]
 dev = [
     "inline-snapshot>=0.32.0",
     "pyrefly>=0.52.0",
+    "pyright>=1.1.408",
     "pytest-asyncio>=1.0.0",
     "ruff>=0.15.1",
 ]

pyproject.toml

@@ -25,32 +25,32 @@ def mangle_function_name(*, name, class_name):
 from typing import Callable
 from typing import ClassVar
 
-MutantDict = Annotated[dict[str, Callable], "Mutant"]
+MutantDict = Annotated[dict[str, Callable], "Mutant"] # type: ignore
 
 
-def _mutmut_trampoline(orig, mutants, call_args, call_kwargs, self_arg = None):
+def _mutmut_trampoline(orig, mutants, call_args, call_kwargs, self_arg = None): # type: ignore
     \"""Forward call to original or mutated function, depending on the environment\"""
-    import os
-    mutant_under_test = os.environ['MUTANT_UNDER_TEST']
-    if mutant_under_test == 'fail':
-        from mutmut.__main__ import MutmutProgrammaticFailException
-        raise MutmutProgrammaticFailException('Failed programmatically')      
-    elif mutant_under_test == 'stats':
-        from mutmut.__main__ import record_trampoline_hit
-        record_trampoline_hit(orig.__module__ + '.' + orig.__name__)
+    import os # type: ignore
+    mutant_under_test = os.environ['MUTANT_UNDER_TEST'] # type: ignore
+    if mutant_under_test == 'fail': # type: ignore
+        from mutmut.__main__ import MutmutProgrammaticFailException # type: ignore
+        raise MutmutProgrammaticFailException('Failed programmatically')       # type: ignore
+    elif mutant_under_test == 'stats': # type: ignore
+        from mutmut.__main__ import record_trampoline_hit # type: ignore
+        record_trampoline_hit(orig.__module__ + '.' + orig.__name__) # type: ignore
         # (for class methods, orig is bound and thus does not need the explicit self argument)
-        result = orig(*call_args, **call_kwargs)
-        return result
-    prefix = orig.__module__ + '.' + orig.__name__ + '__mutmut_'
-    if not mutant_under_test.startswith(prefix):
-        result = orig(*call_args, **call_kwargs)
-        return result
-    mutant_name = mutant_under_test.rpartition('.')[-1]
-    if self_arg is not None:
+        result = orig(*call_args, **call_kwargs) # type: ignore
+        return result # type: ignore
+    prefix = orig.__module__ + '.' + orig.__name__ + '__mutmut_' # type: ignore
+    if not mutant_under_test.startswith(prefix): # type: ignore
+        result = orig(*call_args, **call_kwargs) # type: ignore
+        return result # type: ignore
+    mutant_name = mutant_under_test.rpartition('.')[-1] # type: ignore
+    if self_arg is not None: # type: ignore
         # call to a class method where self is not bound
-        result = mutants[mutant_name](self_arg, *call_args, **call_kwargs)
+        result = mutants[mutant_name](self_arg, *call_args, **call_kwargs) # type: ignore
     else:
-        result = mutants[mutant_name](*call_args, **call_kwargs)
-    return result
+        result = mutants[mutant_name](*call_args, **call_kwargs) # type: ignore
+    return result # type: ignore
 
 """

src/mutmut/trampoline_templates.py

@@ -11,6 +11,13 @@ def test_type_checking_result_snapshot():
                 "type_checking.x_hello__mutmut_2": 1,
                 "type_checking.x_hello__mutmut_3": 1,
                 "type_checking.x_hello__mutmut_4": 1,
+                "type_checking.x_a_hello_wrapper__mutmut_1": 6,
+                "type_checking.x_a_hello_wrapper__mutmut_2": 0,
+                "type_checking.x_mutate_me__mutmut_1": 6,
+                "type_checking.x_mutate_me__mutmut_2": 6,
+                "type_checking.x_mutate_me__mutmut_3": 1,
+                "type_checking.x_mutate_me__mutmut_4": 1,
+                "type_checking.x_mutate_me__mutmut_5": 6,
             }
         }
     )