WIP: Unit tests for channel multiplexer

pkg/sync/spreader_test.go

@@ -0,0 +1,109 @@
+package sync
+
+import (
+	"context"
+	"golang.org/x/sync/errgroup"
+	"testing"
+	"time"
+)
+
+func TestAddedChannelOutput(t *testing.T) {
+	multiplexChannel := make(chan int)
+	outputChannel1 := make(chan int)
+	outputChannel2 := make(chan int)
+	outputChannel3 := make(chan int)
+
+	multiplexer := NewChannelSpreader[int](multiplexChannel)
+
+	multiplexer.AddChannel(outputChannel1)
+	multiplexer.AddChannel(outputChannel2)
+	multiplexer.AddChannel(outputChannel3)
+
+	g, ctx := errgroup.WithContext(context.Background())
+
+	g.Go(func() error {
+		return multiplexer.Run(ctx)
+	})
+
+	want := 10
+
+	multiplexChannel <- want
+
+	if got := <-outputChannel1; got != want {
+		t.Errorf("got '%d' for 1st test channel, wanted '%d'", got, want)
+	}
+	if got := <-outputChannel2; got != want {
+		t.Errorf("got '%d' for 2nd test channel, wanted '%d'", got, want)
+	}
+	if got := <-outputChannel3; got != want {
+		t.Errorf("got '%d' for 3rd test channel, wanted '%d'", got, want)
+	}
+}
+
+func TestCreatedChannelOutput(t *testing.T) {
+	multiplexChannel := make(chan int)
+
+	multiplexer := NewChannelSpreader[int](multiplexChannel)
+
+	outputChannel1 := multiplexer.NewChannel()
+	outputChannel2 := multiplexer.NewChannel()
+	outputChannel3 := multiplexer.NewChannel()
+
+	g, ctx := errgroup.WithContext(context.Background())
+
+	g.Go(func() error {
+		return multiplexer.Run(ctx)
+	})
+
+	want := 10
+
+	multiplexChannel <- want
+
+	if got := <-outputChannel1; got != want {
+		t.Errorf("got '%d' for 1st test channel, wanted '%d'", got, want)
+	}
+	if got := <-outputChannel2; got != want {
+		t.Errorf("got '%d' for 2nd test channel, wanted '%d'", got, want)
+	}
+	if got := <-outputChannel3; got != want {
+		t.Errorf("got '%d' for 3rd test channel, wanted '%d'", got, want)
+	}
+}
+
+func TestClosedChannels(t *testing.T) {
+	multiplexChannel := make(chan int)
+
+	multiplexer := NewChannelSpreader[int](multiplexChannel)
+
+	outputChannel1 := multiplexer.NewChannel()
+	outputChannel2 := multiplexer.NewChannel()
+	outputChannel3 := multiplexer.NewChannel()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	g, ctx := errgroup.WithContext(ctx)
+
+	g.Go(func() error {
+		return multiplexer.Run(ctx)
+	})
+
+	cancel()
+
+	select {
+	case <-outputChannel1:
+	case <-time.After(time.Second):
+		t.Error("1st channel is still open, should be closed")
+	}
+
+	select {
+	case <-outputChannel2:
+	case <-time.After(time.Second):
+		t.Error("2nd channel is still open, should be closed")
+	}
+
+	select {
+	case <-outputChannel3:
+	case <-time.After(time.Second):
+		t.Error("3rd channel is still open, should be closed")
+	}
+
+}