ipn/ipnlocal: on fresh lazy-connecting install, start in state NeedsLogin

Fixes #1759

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/ipnlocal/local_test.go

@@ -5,14 +5,20 @@
 package ipnlocal
 
 import (
+	"bytes"
+	"fmt"
+	"net/http"
 	"reflect"
+	"sync"
 	"testing"
 
 	"inet.af/netaddr"
+	"tailscale.com/ipn"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/netmap"
+	"tailscale.com/wgengine"
 	"tailscale.com/wgengine/wgcfg"
 )
 
@@ -419,3 +425,48 @@ func TestPeerAPIBase(t *testing.T) {
 		})
 	}
 }
+
+type panicOnUseTransport struct{}
+
+func (panicOnUseTransport) RoundTrip(*http.Request) (*http.Response, error) {
+	panic("unexpected HTTP request")
+}
+
+var nl = []byte("\n")
+
+func TestStartsInNeedsLoginState(t *testing.T) {
+	var (
+		mu     sync.Mutex
+		logBuf bytes.Buffer
+	)
+	logf := func(format string, a ...interface{}) {
+		mu.Lock()
+		defer mu.Unlock()
+		fmt.Fprintf(&logBuf, format, a...)
+		if !bytes.HasSuffix(logBuf.Bytes(), nl) {
+			logBuf.Write(nl)
+		}
+	}
+	store := new(ipn.MemoryStore)
+	eng, err := wgengine.NewFakeUserspaceEngine(logf, 0)
+	if err != nil {
+		t.Fatalf("NewFakeUserspaceEngine: %v", err)
+	}
+	lb, err := NewLocalBackend(logf, "logid", store, eng)
+	if err != nil {
+		t.Fatalf("NewLocalBackend: %v", err)
+	}
+
+	lb.SetHTTPTestClient(&http.Client{
+		Transport: panicOnUseTransport{}, // validate we don't send HTTP requests
+	})
+
+	if err := lb.Start(ipn.Options{
+		StateKey: ipn.GlobalDaemonStateKey,
+	}); err != nil {
+		t.Fatalf("Start: %v", err)
+	}
+	if st := lb.State(); st != ipn.NeedsLogin {
+		t.Errorf("State = %v; want NeedsLogin", st)
+	}
+}