[DO NOT MERGE] Skip integration tests with single change

.kokoro/build.sh

@@ -17,14 +17,44 @@ set -eo pipefail
 
 cd github/google-cloud-java/
 
+function client_has_changes() {
+  CLIENT_NAME=$1
+  if [[ ! -z $(git diff master google-cloud-clients/google-cloud-core*) ]]; then
+    echo "true"
+    return
+  fi
+
+  if [[ ! -z $(git diff master google-cloud-clients/${CLIENT_NAME}) ]]; then
+    echo "true"
+    return
+  fi
+
+  if [[ ! -z $(git diff master google-api-grpc/*${CLIENT_NAME}*) ]]; then
+    echo "true"
+    return
+  fi
+
+  echo "false"
+}
+
 # Print out Java version
 java -version
 echo $JOB_TYPE
 
+if [[ "${SKIP_INTEGRATION_TESTS_IF_NO_CHANGES}" == "true" ]] &&
+   [[ "${JOB_TYPE}" == "integration" ]]; then
+  CLIENT=$(echo ${INTEGRATION_TEST_ARGS} | cut -d' ' -f1 | cut -d'/' -f2)
+  CLIENT_HAS_CHANGES=$(client_has_changes ${CLIENT})
+  if [[ "${CLIENT_HAS_CHANGES}" == "false" ]]; then
+    echo "No difference from master, skipping tests."
+    exit 0
+  fi
+fi
+
 mvn install -DskipTests=true -Dmaven.javadoc.skip=true -Dgcloud.download.skip=true -B -V
 
 # prepend Kokoro root directory onto GOOGLE_APPLICATION_CREDENTIALS path
-if [ ! -z "$GOOGLE_APPLICATION_CREDENTIALS" ]; then
+if [[ ! -z "$GOOGLE_APPLICATION_CREDENTIALS" ]]; then
     export GOOGLE_APPLICATION_CREDENTIALS=$(realpath ${KOKORO_ROOT}/src/${GOOGLE_APPLICATION_CREDENTIALS})
 fi
 

.kokoro/common.cfg

@@ -11,3 +11,9 @@ env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
     value: "github/google-auth-library-java/.kokoro/build.sh"
 }
+
+# By default, always run integration tests
+env_vars: {
+  key: "SKIP_INTEGRATION_TESTS_IF_NO_CHANGES"
+  value: "false"
+}

.kokoro/presubmit/common.cfg

@@ -14,13 +14,19 @@ gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
 build_file: "google-cloud-java/.kokoro/trampoline.sh"
 
 env_vars: {
-    key: "TRAMPOLINE_BUILD_FILE"
-    value: "github/google-cloud-java/.kokoro/build.sh"
+  key: "TRAMPOLINE_BUILD_FILE"
+  value: "github/google-cloud-java/.kokoro/build.sh"
 }
 
 env_vars: {
-    key: "JOB_TYPE"
-    value: "test"
+  key: "JOB_TYPE"
+  value: "test"
+}
+
+# For presubmits, only run integrations if the code has changed
+env_vars: {
+  key: "SKIP_INTEGRATION_TESTS_IF_NO_CHANGES"
+  value: "true"
 }
 
 before_action {

google-cloud-clients/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/admin/v2/BaseBigtableInstanceAdminClient.java

@@ -145,6 +145,7 @@
 @Generated("by gapic-generator")
 @BetaApi
 public class BaseBigtableInstanceAdminClient implements BackgroundResource {
+  // trivial comment added to check bigtable integration tests are triggered
   private final BaseBigtableInstanceAdminSettings settings;
   private final BigtableInstanceAdminStub stub;
   private final OperationsClient operationsClient;