Method TestBalancer_OneAddress

balancer/weightedroundrobin/balancer_test.go:173–206

Tests basic functionality with one address. With only one address, load reporting doesn't affect routing at all.

(t *testing.T)

// Tests basic functionality with one address.  With only one address, load
// reporting doesn't affect routing at all.
func (s) TestBalancer_OneAddress(t *testing.T) {
	testCases := []struct {
		rt  reportType
		cfg iwrr.LBConfig
	}{
		{rt: reportNone, cfg: perCallConfig},
		{rt: reportCall, cfg: perCallConfig},
		{rt: reportOOB, cfg: oobConfig},
	}

	for _, tc := range testCases {
		t.Run(fmt.Sprintf("reportType:%v", tc.rt), func(t *testing.T) {
			ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
			defer cancel()

			srv := startServer(t, tc.rt)

			sc := svcConfig(t, tc.cfg)
			if err := srv.StartClient(grpc.WithDefaultServiceConfig(sc)); err != nil {
				t.Fatalf("Error starting client: %v", err)
			}

			// Perform many RPCs to ensure the LB policy works with 1 address.
			for i := 0; i < 100; i++ {
				srv.callMetrics.SetQPS(float64(i))
				srv.oobMetrics.SetQPS(float64(i))
				if _, err := srv.Client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
					t.Fatalf("Error from EmptyCall: %v", err)
				}
				time.Sleep(time.Millisecond) // Delay; test will run 100ms and should perform ~10 weight updates
			}
		})
	}
}

// TestWRRMetricsBasic tests metrics emitted from the WRR balancer. It
// configures a weighted round robin balancer as the top level balancer of a