SDK: Add Shutdown test for Span Processor (#169)

* SDK: Add Shutdown test for Span Processor

* SDK: Shutdown test for Span Processor. Review fixes

sdk/trace/batch_span_processor_test.go

@@ -202,3 +202,19 @@ func getSpanContext() core.SpanContext {
 		TraceFlags: 0x1,
 	}
 }
+
+func TestBatchSpanProcessorShutdown(t *testing.T) {
+	bsp, err := sdktrace.NewBatchSpanProcessor(&testBatchExporter{})
+	if err != nil {
+		t.Errorf("Unexpected error while creating processor\n")
+	}
+
+	if bsp == nil {
+		t.Fatalf("Error creating new instance of BatchSpanProcessor\n")
+	}
+
+	bsp.Shutdown()
+
+	// Multiple call to Shutdown() should not panic.
+	bsp.Shutdown()
+}

sdk/trace/simple_span_processor_test.go

@@ -75,3 +75,12 @@ func TestSimpleSpanProcessorOnEnd(t *testing.T) {
 		t.Errorf("SimplerSpanProcessor OnEnd() check: got %+v, want %+v\n", gotTraceID, wantTraceID)
 	}
 }
+
+func TestSimpleSpanProcessorShutdown(t *testing.T) {
+	ssp := sdktrace.NewSimpleSpanProcessor(&testExporter{})
+	if ssp == nil {
+		t.Errorf("Error creating new instance of SimpleSpanProcessor\n")
+	}
+
+	ssp.Shutdown()
+}

sdk/trace/span_processor_test.go

@@ -109,8 +109,47 @@ func TestUnregisterSpanProcessorWhileSpanIsActive(t *testing.T) {
 	}
 }
 
-// TODO(rghetia): Add Shutdown test when it is implemented.
-func TestShutdown(t *testing.T) {
+func TestSpanProcessorShutdown(t *testing.T) {
+	name := "Increment shutdown counter of a span processor"
+	sp := NewTestSpanProcessor()
+	if sp == nil {
+		t.Fatalf("Error creating new instance of TestSpanProcessor\n")
+	}
+
+	wantCount := sp.shutdownCount + 1
+	sp.Shutdown()
+
+	gotCount := sp.shutdownCount
+	if wantCount != gotCount {
+		t.Errorf("%s: wrong counter: got %d, want %d\n", name, gotCount, wantCount)
+	}
+}
+
+func TestMultipleUnregisterSpanProcessorCalls(t *testing.T) {
+	name := "Increment shutdown counter after each UnregisterSpanProcessor call"
+	sp := NewTestSpanProcessor()
+	if sp == nil {
+		t.Fatalf("Error creating new instance of TestSpanProcessor\n")
+	}
+
+	wantCount := sp.shutdownCount + 1
+
+	sdktrace.RegisterSpanProcessor(sp)
+	sdktrace.UnregisterSpanProcessor(sp)
+
+	gotCount := sp.shutdownCount
+	if wantCount != gotCount {
+		t.Errorf("%s: wrong counter: got %d, want %d\n", name, gotCount, wantCount)
+	}
+
+	// Multiple UnregisterSpanProcessor triggers multiple Shutdown calls.
+	wantCount = wantCount + 1
+	sdktrace.UnregisterSpanProcessor(sp)
+
+	gotCount = sp.shutdownCount
+	if wantCount != gotCount {
+		t.Errorf("%s: wrong counter: got %d, want %d\n", name, gotCount, wantCount)
+	}
 }
 
 func NewTestSpanProcessor() *testSpanProcesor {