# basic
a = ValueError('error test')
assert.equal(a.name, 'ValueError')
assert.equal(a.message, 'error test')
assert.throws(
	def():
		raise a
	,
    /ValueError: error test/
)

# relevant error test
class ArrayishTest:
    def __init__(self, arr):
        self._ = arr
    def get_(self, index):
        if 0 <= index < self._.length:
            return self._[index]
        else:
            raise IndexError()
    def set_(self, index, value):
        if 0 <= index < self._.length:
            self._[index] = value
        else:
            raise IndexError()
b = ArrayishTest([1 to 5])
assert.doesNotThrow(def(): b.get_(3);)
assert.doesNotThrow(def(): b.set_(0, 'hi');)
assert.throws(
    def():
        b.get_(6)
    ,
    IndexError
)
assert.throws(
    def():
        b.set_(-1, 4)
    ,
    /IndexError/
)