test: allow running pytest without specifying the tests directory

This allows `pytest` to be executed from the top-level source or build
directory (or any other directory below).

Change-Id: Ib7af2ea2aaf01319d6839d2dc67228fbb5a7bc34
Reviewed-on: https://code.wireshark.org/review/31370
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

.travis.yml

@@ -72,6 +72,6 @@ before_script:
 script:
   - ninja
   - ninja test-programs
-  - pytest -nauto -v ../test
+  - pytest -nauto -v
 after_script:
   - if [ -f run/tshark ]; then run/tshark --version; fi

CMakeLists.txt

@@ -3170,6 +3170,15 @@ foreach(_group_name ${_test_group_list})
 	set_tests_properties(${_group_name} PROPERTIES TIMEOUT 600)
 endforeach()
 
+# Make it possible to run pytest without passing the full path as argument.
+if(NOT CMAKE_SOURCE_DIR STREQUAL CMAKE_BINARY_DIR)
+	file(READ "${CMAKE_CURRENT_SOURCE_DIR}/pytest.ini" pytest_ini)
+	string(REGEX REPLACE "\naddopts = ([^\n]+)"
+		"\naddopts = ${CMAKE_CURRENT_SOURCE_DIR}/test \\1"
+		pytest_ini "${pytest_ini}")
+	file(WRITE "${CMAKE_BINARY_DIR}/pytest.ini" "${pytest_ini}")
+endif()
+
 if (GIT_EXECUTABLE)
 	# Update AUTHORS file with entries from git shortlog
 	add_custom_target(

appveyor.yml

@@ -58,7 +58,7 @@ before_test:
   - msbuild /m test-programs.vcxproj
 
 test_script:
-  - pytest -nauto ..\test
+  - pytest -nauto
 
 on_finish:
   - ps: |

pytest.ini

@@ -0,0 +1,4 @@
+[pytest]
+testpaths = test
+python_files = suite_*.py group_*.py
+addopts = -ra

test/conftest.py

@@ -6,8 +6,9 @@
 #
 # SPDX-License-Identifier: GPL-2.0-or-later
 #
-'''py.test configuration'''
+'''pytest configuration'''
 
+import re
 import fixtures
 
 def pytest_addoption(parser):
@@ -27,7 +28,11 @@ def pytest_collection_modifyitems(items):
     global _all_test_groups
     suites = []
     for item in items:
-        name = item.nodeid.split("::")[0].replace(".py", "").replace("/", ".")
+        name = item.nodeid.split("::")[0].replace(".py", "")
+        # When executed from the rootdir (e.g. "pytest test"), be sure to strip
+        # all preceding components ("test/suite_io" -> "suite_io").
+        name = re.sub(r'^.*/suite_', 'suite_', name)
+        name = name.replace("/", ".")
         if name not in suites:
             suites.append(name)
     _all_test_groups = sorted(suites)

test/pytest.ini

@@ -1,3 +0,0 @@
-[pytest]
-python_files=suite_*.py group_*.py
-addopts = -ra