move tests folder to pipelines src tree

Author: yuanchi2807

codeflare/pipelines/tests/README.md

@@ -0,0 +1,17 @@
+# Architecture decision record 
+
+Select a test framework for Codeflare pipeline.
+
+Contents:
+
+* [Use pytest as test framework](#use-pytest-as-test-framework)
+* [Unit test coverage](#unit-test-coverage)
+
+## Use pytest as test framework
+PyTest is a testing framework in Python, with simple and easy syntax targeting unit tests and simple functional tests. PyTest can run tests in parallel and automatically detects tests in the test folder. PyTest serves the current goal of testing Codeflare pipelines well. 
+
+## Unit test coverage
+* And node in the pipeline graph
+* Or node in the pipeline graph
+
+