ci: split systests into separate Kokoro session (#481)

Closes #478. Co-authored-by: larkee <31196561+larkee@users.noreply.github.com>

Author: tseaver

.kokoro/presubmit/presubmit.cfg

@@ -1 +1,7 @@
-# Format: //devtools/kokoro/config/proto/build.proto
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Disable system tests.
+env_vars: {
+ key: "RUN_SYSTEM_TESTS"
+ value: "false"
+}

.kokoro/presubmit/system-3.8.cfg

@@ -0,0 +1,7 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Only run this nox session.
+env_vars: {
+ key: "NOX_SESSION"
+ value: "system-3.8"
+}

owlbot.py

@@ -136,7 +136,9 @@ def get_staging_dirs(
 # ----------------------------------------------------------------------------
 # Add templated files
 # ----------------------------------------------------------------------------
-templated_files = common.py_library(microgenerator=True, samples=True, cov_level=99)
+templated_files = common.py_library(
+ microgenerator=True, samples=True, cov_level=99, split_system_tests=True,
+)
 s.move(templated_files, excludes=[".coveragerc"])
 
 # Ensure CI runs on a new instance each time