test: add test to verify lifecycle.rule.condition.age_days = 0 (#1846)

Zero (0) is a special value for some serialization configurations. Add a test to ensure it is properly passed to the backend, and is effective.

google-cloud-storage/src/main/java/com/google/cloud/storage/GrpcConversions.java

@@ -714,8 +714,12 @@ private BucketInfo.LifecycleRule lifecycleRuleDecode(Bucket.Lifecycle.Rule from)
               .collect(ImmutableList.toImmutableList());
       conditionBuilder.setMatchesStorageClass(collect);
     }
-    conditionBuilder.setMatchesPrefix(condition.getMatchesPrefixList());
-    conditionBuilder.setMatchesSuffix(condition.getMatchesSuffixList());
+    if (!condition.getMatchesPrefixList().isEmpty()) {
+      conditionBuilder.setMatchesPrefix(condition.getMatchesPrefixList());
+    }
+    if (!condition.getMatchesSuffixList().isEmpty()) {
+      conditionBuilder.setMatchesSuffix(condition.getMatchesSuffixList());
+    }
     return new BucketInfo.LifecycleRule(lifecycleAction, conditionBuilder.build());
   }
 

google-cloud-storage/src/test/java/com/google/cloud/storage/it/ITBucketLifecycleRulesTest.java

@@ -72,6 +72,22 @@ public void deleteRule_addingALabelToABucketWithASingleDeleteRuleOnlyModifiesThe
     }
   }
 
+  @Test
+  public void condition_ageDays_0_shouldWork() throws Exception {
+    LifecycleRule d1 =
+        new LifecycleRule(
+            LifecycleAction.newAbortIncompleteMPUploadAction(),
+            LifecycleCondition.newBuilder().setAge(0).build());
+    BucketInfo info = baseInfo().setLifecycleRules(ImmutableList.of(d1)).build();
+
+    try (TemporaryBucket tmp =
+        TemporaryBucket.newBuilder().setBucketInfo(info).setStorage(storage).build()) {
+      BucketInfo bucket = tmp.getBucket();
+      Bucket update = storage.get(bucket.getName());
+      assertThat(update.getLifecycleRules()).isEqualTo(ImmutableList.of(d1));
+    }
+  }
+
   @Test
   public void deleteRule_modifyingLifecycleRulesMatchesLastOperation() throws Exception {
     BucketInfo info;