Using InMemorySpanExporter for wsgi/flask tests (#306)
Using InMemorySpanExporter for wsgi/flask tests (#306)

The InMemorySpanExporter provides a friendly interface to retrieving span information, reducing the need for mocking in unit tests.

Signed-off-by: Alex Boten <1e5a92690ae5061b029620512ac8ae33d4f3a3b3@lightstep.com>
open-telemetry/opentelemetry-python-contrib,open-telemetry/opentelemetry-python-contrib,open-telemetry/opentelemetry-python-contrib