test: make it possible to use pytest-style test fixtures

Currently all binaries must be available or no tests will be executed.
This is inconvenient if you just want to test a single binary (e.g.
text2pcap) without having to build epan. The problem is essentially that
tests lack dependency annotations.

To solve this problem, add the required dependencies as parameters to
each test (so-called 'fixtures' in pytest). Skip a test if a binary
(such as tshark) is unavailable. As a demonstration, suite_dissection.py
is converted. Over time, tests should no longer depend on config.py due
to explicit dependencies fixtures (listed in fixtures_ws.py).

Since the unittest module does not support such dependency injections,
create a small glue for use with pytest and an (incomplete) emulation
layer for use with test.py.

Tested with pytest 3.8.2 + Python 3.7.0 and pytest 3.0.3 + Python 3.4.3.
Python 2.7 is not supported and will fail. Test commands:

    ~/wireshark/test/test.py -p ~/build/run
    WS_BIN_PATH=~/build/run pytest ~/wireshark/test -ra

Change-Id: I6dc8c28f5c8b7bbc8f4c04838e9bf085cd22eb0b
Ping-Bug: 14949
Reviewed-on: https://code.wireshark.org/review/30220
Tested-by: Petri Dish Buildbot
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/test/conftest.py b/test/conftest.py
index eff63dadaa..a09e86c485 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -10,9 +10,9 @@
 
 import os
 import sys
+import fixtures
 import config
 
-
 # XXX remove globals in config and create py.test-specific fixtures
 try:
     _program_path = os.environ['WS_BIN_PATH']
@@ -32,3 +32,7 @@ def pytest_collection_modifyitems(items):
         if name not in suites:
             suites.append(name)
     config.all_groups = list(sorted(suites))
+
+# Must enable pytest before importing fixtures_ws.
+fixtures.enable_pytest()
+from fixtures_ws import *