[antlr-interest] antlr python unit testing
Kaleb Pederson
kibab at icehouse.net
Thu May 3 17:02:55 PDT 2007
Hi Laurie,
In python, stdin is just a file descriptor that you can change. So, if you
wanted to manipulate it to read from a file, or some other object that had
the same interface as a file descriptor, you could do so.
For example:
import sys
sys.stdin = open('myfile','r');
Then, if you needed to get the regular stdin back, sys.stdin = sys.__stdin__
So, take advantage of the StringIO class:
import StringIO
import sys
sys.stdin = StringIO.StringIO("My text to be parsed")
Now you can run your unit tests using whatever text you want.
Hope that helps.
--Kaleb
On Thursday 03 May 2007, Laurie Harper wrote:
> I'm using ANTLR for Python and have my lexer and parser partially
> working. I would like to start writing unit tests to identify exactly
> what is and isn't right in what I have so far. (Call it test-first
> debugging ;-)
>
> This is a total newbie question but, how do I pass input into my lexer
> or parser from a Python script, rather than having it come from stdin?
> Ideally, I'd like to create a lexer instance and a parser instance and
> then write unit tests that exercise specific rules with varying input,
> al la:
>
> import unittest
> class LexerTests(unittest.TestCase):
> def setUp(self):
> self.L = lexer()
> self.P = parser(self.L)
>
> def test_lexer(self):
> input = "specimen input"
>
> # *****
> self.L.INJECT_INPUT_CHARACTERS(input)
> # *****
>
> self.failUnlessEqual(some_result, self.L.nextToken())
>
> def test_parser(self):
> input = "specimen input"
>
> # *****
> self.L.INJECT_INPUT_CHARACTERS(input)
> # *****
>
> self.failUnlessEqual(some_result, self.P.someRule()
>
> How do I achieve the INJECT_INPUT_CHARACTERS(input) part?
>
> L.
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