Split single module file out into directory module

tox_poetry_installer/exceptions.py

@@ -0,0 +1,28 @@
+"""Custom plugin exceptions
+
+All exceptions should inherit from the common base exception :exc:`ToxPoetryInstallerException`.
+
+::
+
+  ToxPoetryInstallerException
+   +-- LockedDepVersionConflictError
+   +-- LockedDepNotFoundError
+   +-- ExtraNotFoundError
+
+"""
+
+
+class ToxPoetryInstallerException(Exception):
+    """Error while installing locked dependencies to the test environment"""
+
+
+class LockedDepVersionConflictError(ToxPoetryInstallerException):
+    """Locked dependencies cannot specify an alternate version for installation"""
+
+
+class LockedDepNotFoundError(ToxPoetryInstallerException):
+    """Locked dependency was not found in the lockfile"""
+
+
+class ExtraNotFoundError(ToxPoetryInstallerException):
+    """Project package extra not defined in project's pyproject.toml"""