test: make integration test use Go 1.17.7 (#802)

system-test/integration_test.sh

@@ -27,17 +27,25 @@ export GOOGLE_APPLICATION_CREDENTIALS="${SERVICE_KEY}"
 # Run test.
 cd "system-test"
 
+# Ensure a newer version of Go is used so it is compatible with newer libraries.
+# Here we install v1.17.7 which is the current version as of when this code
+# was written, following instructions from https://go.dev/doc/manage-install.
+# Go modules might not be on for previous versions of Go, so we also have to
+# enable the module system explicitly.
+export GO111MODULE=on
+go install golang.org/dl/go1.17.7
+go1.17.7 download
+
 # Initializing go modules allows our dependencies to install versions of their
 # dependencies specified by their go.mod files. This reduces the likelihood of
 # dependencies breaking this test.
-go version
-go mod init e2e
-retry go get cloud.google.com/go/profiler/proftest@HEAD
-retry go test -c -tags=integration .
+go1.17.7 version
+go1.17.7 mod init e2e
+retry go1.17.7 get cloud.google.com/go/profiler/proftest@HEAD
+retry go1.17.7 test -c -tags=integration .
 
 if [ "$KOKORO_GITHUB_PULL_REQUEST_NUMBER" = "" ]; then
   ./e2e.test -commit="$COMMIT" -branch="$BRANCH" -repo="$REPO" -run_backoff_test=true
 else
   ./e2e.test -commit="$COMMIT" -pr="$KOKORO_GITHUB_PULL_REQUEST_NUMBER"
 fi
-