add fixture to reset threadpool after experimental/api tests

any import from experimental will reset the threadpool to 0
in order to have all other tests run normally, we reset it after
each test module for the experimental tests
further reference:
see ilastik#2517

pytest.ini

@@ -1,6 +1,14 @@
 [pytest]
 qt_api=pyqt5
 python_files = test*.py
-testpaths = tests
+testpaths = tests lazyflow
 markers =
     guitest: mark a test as a gui test
+
+addopts =
+    --doctest-modules
+    --doctest-ignore-import-errors
+    --doctest-continue-on-failure
+    --ignore=tests/test_ilastik/data
+    --ignore=tests/test_ilastik/helpers
+    --ignore=lazyflow/cancel_token.py

setup.cfg

@@ -9,12 +9,3 @@ include_package_data = True
 
 [options.packages.find] #optional
 include=ilastik*, lazyflow*
-
-[tool:pytest]
-python_files = test*.py
-testpaths = tests lazyflow
-addopts =
-    -p no:pytest-qt
-    --doctest-modules
-    --doctest-ignore-import-errors
-    --doctest-continue-on-failure

tests/test_ilastik/test_experimental/conftest.py

@@ -40,3 +40,16 @@ def test_data_lookup(data_path, tmpdir_factory) -> types.ApiTestDataLookup:
             pytest.fail(fail_msg)
 
         return types.ApiTestDataLookup(path_by_name)
+
+
+@pytest.fixture(scope="module", autouse=True)
+def restore_lazyflow_thread_pool():
+    # any import from experimental will reset the threadpool to 0
+    # in order to have all other tests run normally, we reset it after
+    # each test module for the experimental tests
+    # further reference:
+    # see https://github.com/ilastik/ilastik/issues/2517
+    yield
+    import lazyflow
+
+    lazyflow.request.Request.reset_thread_pool()