define playback retry rules and states

internal/playback/retry_test.go

@@ -0,0 +1,91 @@
+package playback
+
+import (
+	"testing"
+	"time"
+)
+
+func TestFiniteAttempts(t *testing.T) {
+	rp := RetryPolicy{
+		MaxAttempts:  3,
+		InitialDelay: 500 * time.Millisecond,
+		MaxDelay:     10 * time.Second,
+	}
+	if !rp.canRetry(1) {
+		t.Fatal("MaxAttempts=3, failed=1, but can't retry")
+	}
+	if !rp.canRetry(2) {
+		t.Fatal("MaxAttempts=3, failed=2, but can't retry")
+	}
+	if rp.canRetry(3) {
+		t.Fatal("MaxAttempts=3, failed=3, but can retry")
+	}
+}
+
+func TestOneAllowedAttempt(t *testing.T) {
+	rp := RetryPolicy{
+		MaxAttempts:  1,
+		InitialDelay: 500 * time.Millisecond,
+		MaxDelay:     10 * time.Second,
+	}
+	if rp.canRetry(1) {
+		t.Fatal("MaxAttempts=1, failed=1, but can retry")
+	}
+}
+
+func TestUnlimitedAttempts(t *testing.T) {
+	rp := RetryPolicy{
+		MaxAttempts:  0,
+		InitialDelay: 500 * time.Millisecond,
+		MaxDelay:     10 * time.Second,
+	}
+	for failedAttempts := 1; failedAttempts <= 10; failedAttempts++ {
+		if !rp.canRetry(failedAttempts) {
+			t.Fatalf(
+				"canRetry(%d) = false for unlimited policy",
+				failedAttempts,
+			)
+		}
+	}
+}
+
+func TestBackoff(t *testing.T) {
+	rp := RetryPolicy{
+		MaxAttempts:  0,
+		InitialDelay: 500 * time.Millisecond,
+		MaxDelay:     10 * time.Second,
+	}
+	want := []time.Duration{
+		500 * time.Millisecond,
+		1 * time.Second,
+		2 * time.Second,
+		4 * time.Second,
+		8 * time.Second,
+		10 * time.Second,
+		10 * time.Second,
+	}
+	for i, wantDelay := range want {
+		failedAttempts := i + 1
+		got := rp.retryDelay(failedAttempts)
+		if got != wantDelay {
+			t.Errorf(
+				"retryDelay(%d) = %s, want %s",
+				failedAttempts,
+				got,
+				wantDelay,
+			)
+		}
+	}
+}
+
+func TestRetryDelayLargeFailureCount(t *testing.T) {
+	policy := RetryPolicy{
+		MaxAttempts:  0,
+		InitialDelay: 500 * time.Millisecond,
+		MaxDelay:     10 * time.Second,
+	}
+
+	if got := policy.retryDelay(1_000_000); got != policy.MaxDelay {
+		t.Fatalf("retryDelay() = %s, want cap %s", got, policy.MaxDelay)
+	}
+}