diff --git a/net/tsaddr/tsaddr_test.go b/net/tsaddr/tsaddr_test.go
index bc7317688..ad98a5160 100644
--- a/net/tsaddr/tsaddr_test.go
+++ b/net/tsaddr/tsaddr_test.go
@@ -4,7 +4,32 @@
 
 package tsaddr
 
-import "testing"
+import (
+	"testing"
+
+	"inet.af/netaddr"
+)
+
+func TestInCrostiniRange(t *testing.T) {
+	tests := []struct {
+		ip   netaddr.IP
+		want bool
+	}{
+		{netaddr.IPv4(192, 168, 0, 1), false},
+		{netaddr.IPv4(100, 101, 102, 103), false},
+		{netaddr.IPv4(100, 115, 92, 0), true},
+		{netaddr.IPv4(100, 115, 92, 5), true},
+		{netaddr.IPv4(100, 115, 92, 255), true},
+		{netaddr.IPv4(100, 115, 93, 40), true},
+		{netaddr.IPv4(100, 115, 94, 1), false},
+	}
+
+	for _, test := range tests {
+		if got := ChromeOSVMRange().Contains(test.ip); got != test.want {
+			t.Errorf("inCrostiniRange(%q) = %v, want %v", test.ip, got, test.want)
+		}
+	}
+}
 
 func TestChromeOSVMRange(t *testing.T) {
 	if got, want := ChromeOSVMRange().String(), "100.115.92.0/23"; got != want {