Rename pow to execution (#11135)

* Rename pow to execution

* Fix complain

* Fix complain

beacon-chain/execution/prometheus_test.go

@@ -0,0 +1,53 @@
+package execution
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+)
+
+// TestCleanup ensures that the cleanup function unregisters the prometheus.Collection
+// also tests the interchangability of the explicit prometheus Register/Unregister
+// and the implicit methods within the collector implementation
+func TestCleanup(t *testing.T) {
+	ctx := context.Background()
+	pc, err := NewPowchainCollector(ctx)
+	assert.NoError(t, err, "Uxpected error caling NewPowchainCollector")
+	unregistered := pc.unregister()
+	assert.Equal(t, true, unregistered, "PowchainCollector.unregister did not return true (via prometheus.DefaultRegistry)")
+	// PowchainCollector is a prometheus.Collector, so we should be able to register it again
+	err = prometheus.Register(pc)
+	assert.NoError(t, err, "Got error from prometheus.Register after unregistering PowchainCollector")
+	// even if it somehow gets registered somewhere else, unregister should work
+	unregistered = pc.unregister()
+	assert.Equal(t, true, unregistered, "PowchainCollector.unregister failed on the second attempt")
+	// and so we should be able to register it again
+	err = prometheus.Register(pc)
+	assert.NoError(t, err, "Got error from prometheus.Register on the second attempt")
+	// ok clean it up one last time for real :)
+	unregistered = prometheus.Unregister(pc)
+	assert.Equal(t, true, unregistered, "prometheus.Unregister failed to unregister PowchainCollector on final cleanup")
+}
+
+// TestCancelation tests that canceling the context passed into
+// NewPowchainCollector cleans everything up as expected. This
+// does come at the cost of an extra channel cluttering up
+// PowchainCollector, just for this test.
+func TestCancelation(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	pc, err := NewPowchainCollector(ctx)
+	assert.NoError(t, err, "Uxpected error caling NewPowchainCollector")
+	ticker := time.NewTicker(10 * time.Second)
+	cancel()
+	select {
+	case <-ticker.C:
+		t.Error("Hit timeout waiting for cancel() to cleanup PowchainCollector")
+	case <-pc.finishChan:
+		break
+	}
+	err = prometheus.Register(pc)
+	assert.NoError(t, err, "Got error from prometheus.Register after unregistering PowchainCollector through canceled context")
+}