Fix flaky test TestSimpleSpanProcessorShutdownHonorsContextCancel

CHANGELOG.md

@@ -23,6 +23,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Adds `otlptracegrpc.WithGRPCConn` and `otlpmetricgrpc.WithGRPCConn` for reusing existing gRPC connection. (#2002)
 - Added a new `schema` module to help parse Schema Files in OTEP 0152 format. (#2267)
 
+### Fixed
+
+- The simple span processor shutdown method returns any context error if there is one and the exporter successfully shuts down. (#2290, #2289)
+
 ## [1.0.1] - 2021-10-01
 
 ### Fixed

sdk/trace/simple_span_processor.go

@@ -90,6 +90,16 @@ func (ssp *simpleSpanProcessor) Shutdown(ctx context.Context) error {
 
 		select {
 		case err = <-done:
+			// It is possible for the exporter to have immediately shut down and
+			// the context to already be done. In that case this select statement
+			// will randomly choose a case. This could result in a different
+			// response for similar scenarios. Instead, double check if the
+			// context is done here and return that error if the exporter shut
+			// down did not return one.
+			if err == nil {
+				// If ctx is not done yet, ctx.Err returns nil.
+				err = ctx.Err()
+			}
 		case <-ctx.Done():
 			err = ctx.Err()
 		}