69 lines
1.8 KiB
Plaintext
69 lines
1.8 KiB
Plaintext
This rule raises an issue when using an ``++assert++`` statement on a tuple literal.
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== Why is this an issue?
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When tested for truthiness, a sequence or collection will evaluate to `False` if it is empty (its ``++__len__++`` method returns 0) and to `True` if it contains at least one element.
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Using the ``assert`` statement on a tuple literal will therefore always fail if the tuple is empty, and always succeed otherwise.
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The ``++assert++`` statement does not take parentheses around its parameters. Calling ``++assert(x, y)++`` will test if the tuple ``++(x, y)++`` is True, which is always the case.
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There are two possible fixes:
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* If your intention is to test the first value of the tuple and use the second value as a message, simply remove the parentheses.
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* If your intention is to check that every element of the tuple is ``++True++``, test each value separately.
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=== Code examples
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==== Noncompliant code example
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[source,python]
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----
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def test_values(a, b):
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assert (a, b) # Noncompliant: will always be True
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----
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==== Compliant solution
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[source,python]
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----
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def test_values(a, b):
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# If you mean to test "a" and use "b" as an error message
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assert a, b
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# If you mean to test the values of "a" and "b"
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assert a and b
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----
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== Resources
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* https://docs.python.org/3/reference/simple_stmts.html#the-assert-statement[Python documentation - The ``++assert++`` statement]
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* https://docs.python.org/3/library/stdtypes.html#truth-value-testing[Python documentation - Truth Value Testing]
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Fix this assertion on a tuple literal; did you mean "assert A, B".
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=== Highlighting
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The tuple parameter
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'''
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== Comments And Links
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(visible only on this page)
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=== deprecates: S1721
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endif::env-github,rspecator-view[]
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