feat(engine): add Reporter with buffered and plain implementations

internal/engine/reporter_test.go

@@ -0,0 +1,56 @@
+package engine
+
+import (
+	"bytes"
+	"strings"
+	"sync"
+	"testing"
+)
+
+func TestBufferedReporterRecordsEventsInOrder(t *testing.T) {
+	r := NewBufferedReporter()
+	r.Progress("m", 1, 3, "step 1")
+	r.Log("m", "hello")
+	r.Progress("m", 2, 3, "step 2")
+
+	ev := r.Events()
+	if len(ev) != 3 {
+		t.Fatalf("want 3 events, got %d", len(ev))
+	}
+	if ev[0].Kind != EventProgress || ev[0].Current != 1 {
+		t.Errorf("event[0] = %+v", ev[0])
+	}
+	if ev[1].Kind != EventLog || ev[1].Message != "hello" {
+		t.Errorf("event[1] = %+v", ev[1])
+	}
+}
+
+func TestBufferedReporterIsConcurrencySafe(t *testing.T) {
+	r := NewBufferedReporter()
+	var wg sync.WaitGroup
+	for i := 0; i < 50; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			r.Progress("m", i, 50, "x")
+		}(i)
+	}
+	wg.Wait()
+	if got := len(r.Events()); got != 50 {
+		t.Fatalf("want 50 events, got %d", got)
+	}
+}
+
+func TestPlainReporterFormat(t *testing.T) {
+	var buf bytes.Buffer
+	r := NewPlainReporter(&buf)
+	r.Progress("packages", 2, 10, "installing tio")
+	r.Log("packages", "pacman: done")
+
+	out := buf.String()
+	for _, want := range []string{"[packages] (2/10) installing tio", "[packages] pacman: done"} {
+		if !strings.Contains(out, want) {
+			t.Errorf("output missing %q; got:\n%s", want, out)
+		}
+	}
+}