refactor(gce): check if acceleratorConfig is not null

Author: edgarulg

clouddriver-google/src/main/java/com/netflix/spinnaker/clouddriver/google/deploy/handlers/BasicGoogleDeployHandler.java

@@ -738,7 +738,8 @@ private void setupMonikerForOperation(
 
   protected void validateAcceleratorConfig(BasicGoogleDeployDescription description) {
     // Accelerators are supported for zonal server groups only.
-    if (!description.getAcceleratorConfigs().isEmpty()
+    if (description.getAcceleratorConfigs() != null
+        && !description.getAcceleratorConfigs().isEmpty()
         && (!description.getRegional() || description.getSelectZones())) {
       throw new IllegalArgumentException(
           "Accelerators are only supported with regional server groups if the zones are specified by the user.");

clouddriver-google/src/test/java/com/netflix/spinnaker/clouddriver/google/deploy/handlers/BasicGoogleDeployHandlerTest.java

@@ -1172,6 +1172,12 @@ void validateAcceleratorConfig_noExceptionForValidConfig() {
     assertDoesNotThrow(() -> basicGoogleDeployHandler.validateAcceleratorConfig(mockDescription));
   }
 
+  @Test
+  void validateAcceleratorConfig_noExceptionForNullConfig() {
+    when(mockDescription.getAcceleratorConfigs()).thenReturn(null);
+    assertDoesNotThrow(() -> basicGoogleDeployHandler.validateAcceleratorConfig(mockDescription));
+  }
+
   @Test
   void validateAcceleratorConfig_validRegionalWithZones() {
     BasicGoogleDeployDescription description = mock(BasicGoogleDeployDescription.class);