`test_update_data` fails when `-x` is in `PYTEST_ADDOPTS`

Bug Report

When I run tests for mypy-1.6.0 and -x is in PYTEST_ADDOPTS then test_update_data fails.

To Reproduce

The following command fails:

PYTEST_ADDOPTS="-x" PATH=/usr/gcc/10/bin:$PATH /usr/bin/tox --recreate -e py39 -- mypy/test/meta/test_update_data.py -vv

Expected Behavior

Interestingly, the following passes (please note -x at the end of line):

PYTEST_ADDOPTS="" PATH=/usr/gcc/10/bin:$PATH /usr/bin/tox --recreate -e py39 -- mypy/test/meta/test_update_data.py -vv -x

Actual Behavior

The relevant part of the output:

E           [case testMissingMultiline]
E           s: str = 42;  i: int = 'foo'  # E: Incompatible types in assignment (expression has type "int", variable has type "str") \
E                                         # E: Incompatible types in assignment (expression has type "str", variable has type "int")
E
E           [case testExtraneous]
E         - s: str = 'foo'
E         + s: str = 'foo'  # E: wrong error
E
E           [case testExtraneousMultiline]
E         - s: str = 'foo'
E         + s: str = 'foo'  # E: foo                             # E: bar
E
E           [case testExtraneousMultilineNonError]
E         - s: str = 'foo'
E         + s: str = 'foo'  # W: foo                             # N: bar
E
E           [case testOutCorrect]
E           s: str = 42
E           [out]
E           main:1: error: Incompatible types in assignment (expression has type "int", variable has type "str")
E
E           [case testOutWrong]
E           s: str = 42
E           [out]
E         - main:1: error: Incompatible types in assignment (expression has type "int", variable has type "str")
E         + main:1: error: foobar
E
E           [case testOutWrongIncremental]
E           s: str = 42
E           [out]
E         - main:1: error: Incompatible types in assignment (expression has type "int", variable has type "str")
E         + main:1: error: foobar
E           [out2]
E         - main:1: error: Incompatible types in assignment (expression has type "int", variable has type "str")
E         + main:1: error: foobar
E
E           [case testWrongMultipleFiles]
E           import a, b
E         - s: str = 42  # E: Incompatible types in assignment (expression has type "int", variable has type "str")
E         + s: str = 42  # E: foo
E           [file a.py]
E         - s1: str = 42  # E: Incompatible types in assignment (expression has type "int", variable has type "str")
E         + s1: str = 42  # E: bar
E           [file b.py]
E         - s2: str = 43  # E: Incompatible types in assignment (expression has type "int", variable has type "str")
E         + s2: str = 43  # E: baz
E           [builtins fixtures/list.pyi]

Your Environment

• Mypy version used: 1.6.0
• Mypy command-line flags: N/A
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.9.16

まず、報告された tox コマンドを mypy/test/meta/test_update_data.py に対して実行し、その後、末尾に -x を指定すると成功するコマンドと比較します。このテストが pytest オプションをどのように扱っているかを調べ、PYTEST_ADDOPTS に -x を指定した場合とコマンドラインで指定した場合の両方でテストが成功するように動作を更新します。