feat(Spanner): run backup tests only when requested explicitly (GoogleCloudPlatform#1691)

Author: saranshdhingra

spanner/test/spannerBackupTest.php

@@ -72,6 +72,9 @@ public static function setUpBeforeClass(): void
         if (!extension_loaded('grpc')) {
             self::markTestSkipped('Must enable grpc extension.');
         }
+        if ('true' !== getenv('GOOGLE_SPANNER_RUN_BACKUP_TESTS')) {
+            self::markTestSkipped('Skipping backup tests.');
+        }
         self::$instanceId = self::requireEnv('GOOGLE_SPANNER_INSTANCE_ID');
 
         $spanner = new SpannerClient([

testing/run_test_suite.sh

@@ -85,14 +85,21 @@ FILES_CHANGED=$(git diff --name-only HEAD $(git merge-base HEAD master))
 if [ -z "$PULL_REQUEST_NUMBER" ]; then
     RUN_ALL_TESTS=1
 else
+    labels=$(curl "https://api.github.com/repos/GoogleCloudPlatform/php-docs-samples/issues/$PULL_REQUEST_NUMBER/labels")
+    
     # Check to see if the repo includes the "kokoro:run-all" label
-    if curl "https://api.github.com/repos/GoogleCloudPlatform/php-docs-samples/issues/$PULL_REQUEST_NUMBER/labels" \
-        | grep -q "kokoro:run-all"; then
+    if  grep -q "kokoro:run-all" <<< $labels; then
         RUN_ALL_TESTS=1
     else
         RUN_ALL_TESTS=0
     fi
 
+    # Check to see if the repo includes the "spanner:run-backup-tests" label
+    # If we intend to run the backup tests in Spanner, we set the env variable
+    if grep -q "spanner:run-backup-tests" <<< $labels; then
+        export GOOGLE_SPANNER_RUN_BACKUP_TESTS=true
+    fi
+
 fi
 
 if [ "${TEST_DIRECTORIES}" = "" ]; then