(fixtures): Replace fixture represenation with a class #12473

Glyphack · 2024-06-18T10:27:53Z

During the sprint we discussed fixing the above issue and thought maybe it's a better idea to add a better represenation to fixtures. To do this without patching the object more, this PR refactors fixtures to have a class with attributes.
The main rational behind that is:

Now we have a type for fixtures makes it easier to check for fixture types and no need to perform cast on objects. Removed monkey patching.
They are no longer functions that carry a class within them.
When you decorate a function with a fixture it's not possible to call it anymore. So it makes more sense for it to not be a function or method.

Example

Previously we had:

===================================== short test summary info ======================================
FAILED tmp31nzhe4b.py::test_something - assert fixt == 42
======================================== 1 failed in 0.03s =========================================

where fixt is a pytest fixture function that is not replaced by it's value(directly used)

Now we print:

===================================== short test summary info ======================================
FAILED tmp31nzhe4b.py::test_something - assert pytest_fixture(<function fixt at *>) == 42 
======================================== 1 failed in 0.03s =========================================

Glyphack · 2024-06-20T11:48:43Z

testing/code/test_source.py

    assert src == "    @pytest.fixture\n    def deco_fixture():\n        assert False\n"
-    # currently Source does not unwrap decorators, testing the
-    # existing behavior here for explicitness, but perhaps we should revisit/change this


This test was introduced in https://github.com/pytest-dev/pytest/pull/6840/files and I updated it to work with the new code. Please let me know what you think.

i wonder if it is a fair hack to set the __wrapped__ attribute to a property that triggers a deprecationwarning

Glyphack · 2024-06-20T15:15:15Z

testing/test_compat.py

@@ -52,8 +51,8 @@ def __getattr__(self, attr):
    with pytest.raises(
        ValueError,
        match=(
-            "could not find real function of <Evil left=800>\n"
-            "stopped at <Evil left=800>"
+            "could not find real function of <Evil left=900>\n"


explanation: previously we were doing 2 get attributes but it's now replaced by isinstance check. So left is 100 more.

This is an internal class users don't need to know about it.

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Glyphack · 2024-07-04T18:48:51Z

Hey @The-Compiler @RonnyPfannschmidt I rebased the PR could you please take a look?

changelog/11525.improvement.rst

webknjaz · 2024-07-04T19:46:07Z

src/_pytest/compat.py

 def get_real_func(obj):
    """Get the real function object of the (possibly) wrapped object by
-    functools.wraps or functools.partial."""
+    functools.wraps or functools.partial or pytest.fixture"""
+    from _pytest.fixtures import FixtureFunctionDefinition


Is it possible to have this import at the top?

This is cyclic if I remember correctly. I will try to move it to a another file and try to resolve it

src/_pytest/compat.py

src/_pytest/fixtures.py

webknjaz · 2024-07-04T19:58:01Z

testing/code/test_source.py

@@ -478,12 +478,13 @@ def deco_mark():
    def deco_fixture():
        assert False

-    src = inspect.getsource(deco_fixture)
+    # Since deco_fixture is now an instance of FixtureFunctionDef the getsource function will not work on it.
+    with pytest.raises(Exception):


Could you assert against a more specific exception? As I understand, this is not testing that something went wrong but it's not clear what exactly. Also, it's usually a good idea to use the match= regex with this helper.

Yes will apply. This tries to document the behavior more than testing anything. Before introducing the FixtureFunctionDefinition it was possible to run inspect.getsource on fixtures but now it's not. This is just describing the behavior. I'm open to removing it as well.

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

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Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

Glyphack commented Jun 20, 2024

View reviewed changes

Glyphack changed the title ~~(assertion): Use repr for pytest fixtures and set repr for pytest fixtures~~ (fixtures): Replace fixture represenation with a class Jun 20, 2024

psf-chronographer bot added the bot:chronographer:provided (automation) changelog entry is part of PR label Jun 20, 2024

Glyphack force-pushed the reprs-assert-callable branch 3 times, most recently from bf90fca to d25a8d9 Compare June 20, 2024 13:51

Glyphack commented Jun 20, 2024

View reviewed changes

Glyphack marked this pull request as ready for review June 20, 2024 15:19

Glyphack force-pushed the reprs-assert-callable branch from 260b5a7 to 356a201 Compare July 4, 2024 18:46

Glyphack and others added 21 commits July 4, 2024 20:48

feat: use repr for pytest fixtures

5a06546

(fixture) create a new class to represent fixtures

d3c27d7

fix: update code to use new fixture definitions

4998ca8

Update AUTHORS

bfa47e2

chore: add changelog entry

8f02cd1

add test case for asserting missing fixture

f024ff6

refactor: removed PytestWrapper class

c5e198d

chore: update changelog

c9b9edd

refactor: remove _pytestfixturefunction attribute

cb38db6

refactor: remove unused code

a17d246

ci: set no cover for test function

db30fb1

docs: fix docstring

a362a20

refactor: replace attribute check with type check

f696142

chore: update changelog

f21d1ab

test: add test for _get_wrapped_function

e3b8fa3

refactor: remove unused code

afac29e

refactor: replace type with isinstance

1580241

docs: update docstring

4cd6809

refactor: use instance check to print repr

0096e35

docs: ignore FixtureFunctionDefinition from docs

851d276

This is an internal class users don't need to know about it.

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Glyphack force-pushed the reprs-assert-callable branch from 3d2ec33 to 84cc5b7 Compare July 4, 2024 18:48

webknjaz reviewed Jul 4, 2024

View reviewed changes

Glyphack and others added 5 commits July 4, 2024 14:16

Update changelog/11525.improvement.rst

eb3ee8c

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

Update src/_pytest/fixtures.py

76add4b

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

Update src/_pytest/fixtures.py

5158053

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

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Update src/_pytest/compat.py

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Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk.cvs.github@sydorenko.org.ua>

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(fixtures): Replace fixture represenation with a class #12473

(fixtures): Replace fixture represenation with a class #12473

Glyphack commented Jun 18, 2024 •

edited

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Glyphack Jun 20, 2024

RonnyPfannschmidt Jul 10, 2024

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Glyphack commented Jul 4, 2024

webknjaz Jul 4, 2024

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Glyphack Jul 4, 2024

(fixtures): Replace fixture represenation with a class #12473

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(fixtures): Replace fixture represenation with a class #12473

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Glyphack commented Jun 18, 2024 • edited Loading

Example

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Glyphack commented Jun 18, 2024 •

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