Add upgrade tests to test script (#847)

Summary:
Pull Request resolved: #847

Internal tests will never catch the use of Python features
(like the pipe operator on types without `__future__.annotations`)
that are incompatible with older versions of Python that we still
need to support.

As a result it's very important that we cover this in gituhub tests;
even though we frequently break CI, this at least makes it easy to
prep for an open-source release: first check CI for test failures
on any supported Python version and fix issues, only then start a
release.

Unfortunately the script wasn't running upgrade tests, and as a result
didn't catch an invalid use of the pipe operator in unguarded type
annotations.

Reviewed By: connernilsen

Differential Revision: D57218140

fbshipit-source-id: 26ccd957947b8ba4532ba867488be0d75acd9a92

scripts/run-python-tests.sh

@@ -6,7 +6,7 @@
 
 set -e
 
-SCRIPTS_DIRECTORY="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+SCRIPTS_DIRECTORY="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
 
 # For open-source tests to work, we have to run them from one directory
 # higher than the project root, so that the project root is treated as a
@@ -18,7 +18,6 @@ cd "${SCRIPTS_DIRECTORY}/.."
 ROOT_DIRECTORY="$(pwd)"
 ROOT_DIRECTORY_BASE="$(basename "${ROOT_DIRECTORY}")"
 
-
 # run pyre-extensions tests first: we want to test lower-level code
 # first since higher-level test failures are less informative
 
@@ -36,7 +35,6 @@ fi
 echo ' Running all tests:'
 echo "${files}" | xargs testslide
 
-
 # Test pyre client code last since that's the highest-level code.
 
 cd "${ROOT_DIRECTORY}/.."
@@ -52,3 +50,7 @@ fi
 
 echo ' Running client tests:'
 echo "${files}" | xargs testslide
+
+files=$(find "${ROOT_DIRECTORY_BASE}/tools/upgrade" -name '*_test.py')
+echo ' Running upgrade tests:'
+echo "${files}" | xargs testslide