platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/refresh_coordinator_test.go

@@ -0,0 +1,80 @@
+package app
+
+import (
+	"testing"
+	"time"
+)
+
+func TestRefreshCoordinatorLifecycle(t *testing.T) {
+	now := time.Date(2026, time.March, 9, 21, 0, 0, 0, time.UTC)
+	rc := newRefreshCoordinator(10*time.Minute, 2*time.Second, 60*time.Second)
+
+	if !rc.shouldRefresh(now, false, false) {
+		t.Fatalf("expected refresh when cache is empty")
+	}
+	if !rc.beginRefresh(now, false, false) {
+		t.Fatalf("expected beginRefresh=true for empty cache")
+	}
+	if rc.shouldRefresh(now, false, false) {
+		t.Fatalf("must not refresh while refresh is in progress")
+	}
+
+	rc.finishSuccess(now)
+	snap := rc.snapshot(now)
+	if snap.RefreshInProgress {
+		t.Fatalf("refresh must be finished after success")
+	}
+	if snap.Stale {
+		t.Fatalf("fresh snapshot must not be stale")
+	}
+	if snap.LastError != "" || snap.NextRetryAt != "" {
+		t.Fatalf("success must clear error and retry metadata: %#v", snap)
+	}
+
+	if rc.shouldRefresh(now.Add(5*time.Minute), false, true) {
+		t.Fatalf("fresh cache should not refresh yet")
+	}
+	if !rc.shouldRefresh(now.Add(11*time.Minute), false, true) {
+		t.Fatalf("stale cache should refresh")
+	}
+}
+
+func TestRefreshCoordinatorBackoffAndReset(t *testing.T) {
+	start := time.Date(2026, time.March, 9, 21, 5, 0, 0, time.UTC)
+	rc := newRefreshCoordinator(10*time.Minute, 2*time.Second, 60*time.Second)
+
+	type step struct {
+		at       time.Time
+		expected time.Duration
+	}
+	steps := []step{
+		{at: start, expected: 2 * time.Second},
+		{at: start.Add(2 * time.Second), expected: 4 * time.Second},
+		{at: start.Add(6 * time.Second), expected: 8 * time.Second},
+		{at: start.Add(14 * time.Second), expected: 16 * time.Second},
+		{at: start.Add(30 * time.Second), expected: 32 * time.Second},
+		{at: start.Add(62 * time.Second), expected: 60 * time.Second},
+	}
+
+	for i, st := range steps {
+		rc.finishError("probe failed", st.at)
+		got := rc.nextRetryAt().Sub(st.at)
+		if got != st.expected {
+			t.Fatalf("step=%d unexpected backoff: got=%s want=%s", i+1, got, st.expected)
+		}
+		if rc.lastError() == "" {
+			t.Fatalf("step=%d expected non-empty lastError", i+1)
+		}
+	}
+
+	rc.finishSuccess(start.Add(2 * time.Minute))
+	if rc.consecutiveErrors() != 0 {
+		t.Fatalf("expected consecutiveErrors reset, got %d", rc.consecutiveErrors())
+	}
+	if !rc.nextRetryAt().IsZero() {
+		t.Fatalf("expected nextRetryAt reset")
+	}
+	if rc.lastError() != "" {
+		t.Fatalf("expected lastError reset, got %q", rc.lastError())
+	}
+}