/pyflakes/test/test_other.py

# (c) 2005-2010 Divmod, Inc.
# See LICENSE file for details

"""
Tests for various Pyflakes behavior.
"""

from sys import version_info

from pyflakes import messages as m
from pyflakes.test import harness


class Test(harness.Test):

    def test_duplicateArgs(self):
        self.flakes('def fu(bar, bar): pass', m.DuplicateArgument)

    def test_localReferencedBeforeAssignment(self):
        self.flakes('''
        a = 1
        def f():
            a; a=1
        f()
        ''', m.UndefinedName)
    test_localReferencedBeforeAssignment.todo = 'this requires finding all assignments in the function body first'

    def test_redefinedFunction(self):
        """
        Test that shadowing a function definition with another one raises a
        warning.
        """
        self.flakes('''
        def a(): pass
        def a(): pass
        ''', m.RedefinedFunction)

    def test_redefinedClassFunction(self):
        """
        Test that shadowing a function definition in a class suite with another
        one raises a warning.
        """
        self.flakes('''
        class A:
            def a(): pass
            def a(): pass
        ''', m.RedefinedFunction)

    def test_functionDecorator(self):
        """
        Test that shadowing a function definition with a decorated version of
        that function does not raise a warning.
        """
        self.flakes('''
        from somewhere import somedecorator

        def a(): pass
        a = somedecorator(a)
        ''')

    def test_classFunctionDecorator(self):
        """
        Test that shadowing a function definition in a class suite with a
        decorated version of that function does not raise a warning.
        """
        self.flakes('''
        class A:
            def a(): pass
            a = classmethod(a)
        ''')

    def test_unaryPlus(self):
        '''Don't die on unary +'''
        self.flakes('+1')


    def test_undefinedBaseClass(self):
        """
        If a name in the base list of a class definition is undefined, a
        warning is emitted.
        """
        self.flakes('''
        class foo(foo):
            pass
        ''', m.UndefinedName)


    def test_classNameUndefinedInClassBody(self):
        """
        If a class name is used in the body of that class's definition and
        the name is not already defined, a warning is emitted.
        """
        self.flakes('''
        class foo:
            foo
        ''', m.UndefinedName)


    def test_classNameDefinedPreviously(self):
        """
        If a class name is used in the body of that class's definition and
        the name was previously defined in some other way, no warning is
        emitted.
        """
        self.flakes('''
        foo = None
        class foo:
            foo
        ''')


    def test_comparison(self):
        """
        If a defined name is used on either side of any of the six comparison
        operators, no warning is emitted.
        """
        self.flakes('''
        x = 10
        y = 20
        x < y
        x <= y
        x == y
        x != y
        x >= y
        x > y
        ''')


    def test_identity(self):
        """
        If a deefined name is used on either side of an identity test, no
        warning is emitted.
        """
        self.flakes('''
        x = 10
        y = 20
        x is y
        x is not y
        ''')


    def test_containment(self):
        """
        If a defined name is used on either side of a containment test, no
        warning is emitted.
        """
        self.flakes('''
        x = 10
        y = 20
        x in y
        x not in y
        ''')


    def test_loopControl(self):
        """
        break and continue statements are supported.
        """
        self.flakes('''
        for x in [1, 2]:
            break
        ''')
        self.flakes('''
        for x in [1, 2]:
            continue
        ''')


    def test_ellipsis(self):
        """
        Ellipsis in a slice is supported.
        """
        self.flakes('''
        [1, 2][...]
        ''')


    def test_extendedSlice(self):
        """
        Extended slices are supported.
        """
        self.flakes('''
        x = 3
        [1, 2][x,:]
        ''')



class TestUnusedAssignment(harness.Test):
    """
    Tests for warning about unused assignments.
    """

    def test_unusedVariable(self):
        """
        Warn when a variable in a function is assigned a value that's never
        used.
        """
        self.flakes('''
        def a():
            b = 1
        ''', m.UnusedVariable)


    def test_assignToGlobal(self):
        """
        Assigning to a global and then not using that global is perfectly
        acceptable. Do not mistake it for an unused local variable.
        """
        self.flakes('''
        b = 0
        def a():
            global b
            b = 1
        ''')


    def test_assignToMember(self):
        """
        Assigning to a member of another object and then not using that member
        variable is perfectly acceptable. Do not mistake it for an unused
        local variable.
        """
        # XXX: Adding this test didn't generate a failure. Maybe not
        # necessary?
        self.flakes('''
        class b:
            pass
        def a():
            b.foo = 1
        ''')


    def test_assignInForLoop(self):
        """
        Don't warn when a variable in a for loop is assigned to but not used.
        """
        self.flakes('''
        def f():
            for i in range(10):
                pass
        ''')


    def test_assignInListComprehension(self):
        """
        Don't warn when a variable in a list comprehension is assigned to but
        not used.
        """
        self.flakes('''
        def f():
            [None for i in range(10)]
        ''')


    def test_generatorExpression(self):
        """
        Don't warn when a variable in a generator expression is assigned to but not used.
        """
        self.flakes('''
        def f():
            (None for i in range(10))
        ''')


    def test_assignmentInsideLoop(self):
        """
        Don't warn when a variable assignment occurs lexically after its use.
        """
        self.flakes('''
        def f():
            x = None
            for i in range(10):
                if i > 2:
                    return x
                x = i * 2
        ''')


    def test_tupleUnpacking(self):
        """
        Don't warn when a variable included in tuple unpacking is unused. It's
        very common for variables in a tuple unpacking assignment to be unused
        in good Python code, so warning will only create false positives.
        """
        self.flakes('''
        def f():
            (x, y) = 1, 2
        ''')


    def test_listUnpacking(self):
        """
        Don't warn when a variable included in list unpacking is unused.
        """
        self.flakes('''
        def f():
            [x, y] = [1, 2]
        ''')


    def test_closedOver(self):
        """
        Don't warn when the assignment is used in an inner function.
        """
        self.flakes('''
        def barMaker():
            foo = 5
            def bar():
                return foo
            return bar
        ''')


    def test_doubleClosedOver(self):
        """
        Don't warn when the assignment is used in an inner function, even if
        that inner function itself is in an inner function.
        """
        self.flakes('''
        def barMaker():
            foo = 5
            def bar():
                def baz():
                    return foo
            return bar
        ''')



class Python25Test(harness.Test):
    """
    Tests for checking of syntax only available in Python 2.5 and newer.
    """
    if version_info < (2, 5):
        skip = "Python 2.5 required for if-else and with tests"

    def test_ifexp(self):
        """
        Test C{foo if bar else baz} statements.
        """
        self.flakes("a = 'moo' if True else 'oink'")
        self.flakes("a = foo if True else 'oink'", m.UndefinedName)
        self.flakes("a = 'moo' if True else bar", m.UndefinedName)


    def test_withStatementNoNames(self):
        """
        No warnings are emitted for using inside or after a nameless C{with}
        statement a name defined beforehand.
        """
        self.flakes('''
        from __future__ import with_statement
        bar = None
        with open("foo"):
            bar
        bar
        ''')

    def test_withStatementSingleName(self):
        """
        No warnings are emitted for using a name defined by a C{with} statement
        within the suite or afterwards.
        """
        self.flakes('''
        from __future__ import with_statement
        with open('foo') as bar:
            bar
        bar
        ''')


    def test_withStatementAttributeName(self):
        """
        No warnings are emitted for using an attribute as the target of a
        C{with} statement.
        """
        self.flakes('''
        from __future__ import with_statement
        import foo
        with open('foo') as foo.bar:
            pass
        ''')


    def test_withStatementSubscript(self):
        """
        No warnings are emitted for using a subscript as the target of a
        C{with} statement.
        """
        self.flakes('''
        from __future__ import with_statement
        import foo
        with open('foo') as foo[0]:
            pass
        ''')


    def test_withStatementSubscriptUndefined(self):
        """
        An undefined name warning is emitted if the subscript used as the
        target of a C{with} statement is not defined.
        """
        self.flakes('''
        from __future__ import with_statement
        import foo
        with open('foo') as foo[bar]:
            pass
        ''', m.UndefinedName)


    def test_withStatementTupleNames(self):
        """
        No warnings are emitted for using any of the tuple of names defined by
        a C{with} statement within the suite or afterwards.
        """
        self.flakes('''
        from __future__ import with_statement
        with open('foo') as (bar, baz):
            bar, baz
        bar, baz
        ''')


    def test_withStatementListNames(self):
        """
        No warnings are emitted for using any of the list of names defined by a
        C{with} statement within the suite or afterwards.
        """
        self.flakes('''
        from __future__ import with_statement
        with open('foo') as [bar, baz]:
            bar, baz
        bar, baz
        ''')


    def test_withStatementComplicatedTarget(self):
        """
        If the target of a C{with} statement uses any or all of the valid forms
        for that part of the grammar (See
        U{http://docs.python.org/reference/compound_stmts.html#the-with-statement}),
        the names involved are checked both for definedness and any bindings
        created are respected in the suite of the statement and afterwards.
        """
        self.flakes('''
        from __future__ import with_statement
        c = d = e = g = h = i = None
        with open('foo') as [(a, b), c[d], e.f, g[h:i]]:
            a, b, c, d, e, g, h, i
        a, b, c, d, e, g, h, i
        ''')


    def test_withStatementSingleNameUndefined(self):
        """
        An undefined name warning is emitted if the name first defined by a
        C{with} statement is used before the C{with} statement.
        """
        self.flakes('''
        from __future__ import with_statement
        bar
        with open('foo') as bar:
            pass
        ''', m.UndefinedName)


    def test_withStatementTupleNamesUndefined(self):
        """
        An undefined name warning is emitted if a name first defined by a the
        tuple-unpacking form of the C{with} statement is used before the
        C{with} statement.
        """
        self.flakes('''
        from __future__ import with_statement
        baz
        with open('foo') as (bar, baz):
            pass
        ''', m.UndefinedName)


    def test_withStatementSingleNameRedefined(self):
        """
        A redefined name warning is emitted if a name bound by an import is
        rebound by the name defined by a C{with} statement.
        """
        self.flakes('''
        from __future__ import with_statement
        import bar
        with open('foo') as bar:
            pass
        ''', m.RedefinedWhileUnused)


    def test_withStatementTupleNamesRedefined(self):
        """
        A redefined name warning is emitted if a name bound by an import is
        rebound by one of the names defined by the tuple-unpacking form of a
        C{with} statement.
        """
        self.flakes('''
        from __future__ import with_statement
        import bar
        with open('foo') as (bar, baz):
            pass
        ''', m.RedefinedWhileUnused)


    def test_withStatementUndefinedInside(self):
        """
        An undefined name warning is emitted if a name is used inside the
        body of a C{with} statement without first being bound.
        """
        self.flakes('''
        from __future__ import with_statement
        with open('foo') as bar:
            baz
        ''', m.UndefinedName)


    def test_withStatementNameDefinedInBody(self):
        """
        A name defined in the body of a C{with} statement can be used after
        the body ends without warning.
        """
        self.flakes('''
        from __future__ import with_statement
        with open('foo') as bar:
            baz = 10
        baz
        ''')


    def test_withStatementUndefinedInExpression(self):
        """
        An undefined name warning is emitted if a name in the I{test}
        expression of a C{with} statement is undefined.
        """
        self.flakes('''
        from __future__ import with_statement
        with bar as baz:
            pass
        ''', m.UndefinedName)

        self.flakes('''
        from __future__ import with_statement
        with bar as bar:
            pass
        ''', m.UndefinedName)



class Python27Test(harness.Test):
    """
    Tests for checking of syntax only available in Python 2.7 and newer.
    """
    if version_info < (2, 7):
        skip = "Python 2.7 required for dict/set comprehension tests"

    def test_dictComprehension(self):
        """
        Dict comprehensions are properly handled.
        """
        self.flakes('''
        a = {1: x for x in range(10)}
        ''')

    def test_setComprehensionAndLiteral(self):
        """
        Set comprehensions are properly handled.
        """
        self.flakes('''
        a = {1, 2, 3}
        b = {x for x in range(10)}
        ''')