enable easy checkout switch (#5645)

* enable easy checkout switch

allow having multiple repository checkouts and not needing to remember to rerun 'pip install -e .[dev]' when switching between checkouts and running tests.

* make isort happy

* examples needs one too

examples/conftest.py

+# tests directory-specific settings - this file is run automatically
+# by pytest before any tests are run
+
+import sys
+from os.path import abspath, dirname, join
+
+
+# allow having multiple repository checkouts and not needing to remember to rerun
+# 'pip install -e .[dev]' when switching between checkouts and running tests.
+git_repo_path = abspath(join(dirname(dirname(__file__)), "src"))
+sys.path.insert(1, git_repo_path)

tests/conftest.py

+# tests directory-specific settings - this file is run automatically
+# by pytest before any tests are run
+
+import sys
+from os.path import abspath, dirname, join
+
+
+# allow having multiple repository checkouts and not needing to remember to rerun
+# 'pip install -e .[dev]' when switching between checkouts and running tests.
+git_repo_path = abspath(join(dirname(dirname(__file__)), "src"))
+sys.path.insert(1, git_repo_path)