github.com/k14s/starlark-go@v0.0.0-20200720175618-3a5c849cc368/starlark/testdata/bool.star (about)

     1  # Tests of Starlark 'bool'
     2  # option:float
     3  
     4  load("assert.star", "assert")
     5  
     6  # truth
     7  assert.true(True)
     8  assert.true(not False)
     9  assert.true(not not True)
    10  assert.true(not not 1 >= 1)
    11  
    12  # bool conversion
    13  assert.eq(
    14      [bool(), bool(1), bool(0), bool("hello"), bool("")],
    15      [False, True, False, True, False],
    16  )
    17  
    18  # comparison
    19  assert.true(None == None)
    20  assert.true(None != False)
    21  assert.true(None != True)
    22  assert.eq(1 == 1, True)
    23  assert.eq(1 == 2, False)
    24  assert.true(False == False)
    25  assert.true(True == True)
    26  
    27  # ordered comparison
    28  assert.true(False < True)
    29  assert.true(False <= True)
    30  assert.true(False <= False)
    31  assert.true(True > False)
    32  assert.true(True >= False)
    33  assert.true(True >= True)
    34  
    35  # conditional expression
    36  assert.eq(1 if 3 > 2 else 0, 1)
    37  assert.eq(1 if "foo" else 0, 1)
    38  assert.eq(1 if "" else 0, 0)
    39  
    40  # short-circuit evaluation of 'and' and 'or':
    41  # 'or' yields the first true operand, or the last if all are false.
    42  assert.eq(0 or "" or [] or 0, 0)
    43  assert.eq(0 or "" or [] or 123 or 1 // 0, 123)
    44  assert.fails(lambda : 0 or "" or [] or 0 or 1 // 0, "division by zero")
    45  
    46  # 'and' yields the first false operand, or the last if all are true.
    47  assert.eq(1 and "a" and [1] and 123, 123)
    48  assert.eq(1 and "a" and [1] and 0 and 1 // 0, 0)
    49  assert.fails(lambda : 1 and "a" and [1] and 123 and 1 // 0, "division by zero")
    50  
    51  # Built-ins that want a bool want an actual bool, not a truth value.
    52  # See github.com/bazelbuild/starlark/issues/30
    53  assert.eq(''.splitlines(True), [])
    54  assert.fails(lambda: ''.splitlines(1), 'got int, want bool')
    55  assert.fails(lambda: ''.splitlines("hello"), 'got string, want bool')
    56  assert.fails(lambda: ''.splitlines(0.0), 'got float, want bool')