Integration tests do not clean up instances under an exception

[hengfengli]

Environment details

spanner/v1.49.2

Steps to reproduce

When the following code has a timeout exception, the created instance will not be cleaned up.

java-spanner/google-cloud-spanner/src/test/java/com/google/cloud/spanner/IntegrationTestEnv.java

Line 124 in ce93f87

createdInstance = op.get(30000L, TimeUnit.MILLISECONDS);

I get the following exception:

Caused by: java.util.concurrent.TimeoutException: Waited 30000 milliseconds (plus 129893 nanoseconds delay) for com.google.common.util.concurrent.AbstractCatchingFuture$CatchingFuture@26b95b0b[status=PENDING, info=[inputFuture=[com.google.api.core.ApiFutureToListenableFuture@5f7da3d3], exceptionType=[class java.lang.Exception], fallback=[com.google.api.core.ApiFutures$GaxFunctionToGuavaFunction@103082dd]]]
        at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:509)
        at com.google.common.util.concurrent.FluentFuture$TrustedFuture.get(FluentFuture.java:102)
        at com.google.common.util.concurrent.ForwardingFuture.get(ForwardingFuture.java:68)
        at com.google.api.gax.longrunning.OperationFutureImpl.get(OperationFutureImpl.java:133)
        at com.google.cloud.spanner.IntegrationTestEnv.initializeInstance(IntegrationTestEnv.java:124)
        ... 21 more

But the instance is created successfully but is not deleted. Then, all subsequent tests fail with "Instance already exists" error:

com.google.cloud.spanner.SpannerException: ALREADY_EXISTS: com.google.cloud.spanner.SpannerException: ALREADY_EXISTS: io.grpc.StatusRuntimeException: ALREADY_EXISTS: Instance already exists: projects/test-project/instances/test-instance

Expected behaviour

If a test fails with an exception but an instance is created, the instance should be deleted properly and it should not affect the subsequent tests.