demandimport: add support for PyPy
PyPy's implementation of __import__ differs subtly from that of CPython.
If invoked without a name or fromlist, it throws an ImportError,
whereas CPython returns a reference to the level-appropriate importing
package.
Here, we achieve the same behaviour by hand.
import os
if os.environ.get('COVERAGE_PROCESS_START'):
try:
import coverage
import random
# uuid is better, but not available in Python 2.4.
covpath = os.path.join(os.environ['COVERAGE_DIR'],
'cov.%s' % random.randrange(0, 1000000000000))
cov = coverage.coverage(data_file=covpath, auto_data=True)
cov._warn_no_data = False
cov._warn_unimported_source = False
cov.start()
except ImportError:
pass