public function testPartitionBy()
{
$expected = [[0, 1], ["foo", "bar"], [2, 3], ["bar", "baz"]];
$xf = t::partitionBy('is_string');
$actual = t::into([], $xf, [0, 1, "foo", "bar", 2, 3, "bar", "baz"]);
$this->assertEquals($expected, $actual);
}
