git-covered

#!/usr/bin/env python

"Run me to check if there's any new code that doesn't have test coverage."

import os
import os.path
import pickle
import re

import git
from coverage import coverage


def get_changed_lines(diff_string):
    """
    Given a unified diff, return the line numbers (as ints) in the new version
    which have been touched.
    """
    ret = set()
    lines = {}
    for hunk in iter(diff_string.split('\n@@')):
        m = re.match(r'\s+-(\d+),(\d+)\s+\+(\d+),(\d+)\s+@@', hunk)
        if m:
            _, _, start, num = m.groups()
            current_line = int(start)
            for line in hunk.split('\n')[1:]:
                if line.startswith(' '):
                    # This is a normal context line.
                    current_line += 1
                elif line.startswith('+'):
                    # We're adding this line.
                    current_line += 1
                    lines[current_line] = line[1:]
                    ret.add(current_line)
    return ret, lines


def print_file_summary(path, uncovered, lines):
    """
    Print a summary of the uncovered new lines in a given file.

    path
        Relative path to this file.

    uncovered
        A set of uncovered line numbers.

    lines
        A dict of line number (int) -> line text with code lines.
    """
    if len(uncovered) > 0:
        print "%s:" % path
        uncovered = list(uncovered)
        uncovered.sort()
        prev = uncovered[0]
        for n in uncovered:
            if n > (prev + 1):
                print "  ------"
            prev = n
            print "  %d: %s" % (n, lines[n + 1])


# Set up .coverage file data.
cov = coverage(auto_data=True)
cov.data.read()

# Set up git repo object.
cwd = os.getcwd()
repo = git.Repo(cwd)

diffs = git.Diff.list_from_string(repo, repo.git.diff('HEAD', '--'))

for diff in diffs:
    path = diff.b_path
    if path.endswith('.py'):
        touched, lines = get_changed_lines(diff.diff)

        _, _, unexecuted, _ = cov.analysis([path])
        uncovered = set(unexecuted).intersection(touched)
        print_file_summary(path, uncovered, lines)