CliRunner.invoke(..., prog_name) not working

[floomy]

Trying to call CliRunner.invoke with the prog_name argument fails for me, any ideas? Thanks!

from click import argument, command, echo
from click.testing import CliRunner


@command()
@argument('greeting')
def main(greeting):
    echo(greeting)

>>> runner = CliRunner().invoke(main, args=['hello'])
>>> runner.exit_code
0
>>> runner.output
'hello\n'

>>> runner = CliRunner().invoke(main, args=['hello'], prog_name='foobar')
>>> runner.exit_code
-1
>>> runner.output
''

Python 3.5.2 with click 6.6.

[kporangehat]

Setting catch_exceptions=False will shows the exception that's occurring:

runner = CliRunner().invoke(main, args=['hello'], catch_exceptions=False, prog_name="foobar")

Raises:

TypeError: main() got multiple values for keyword argument 'prog_name'