From 18fb3f00a861c8a9fd3f2ddb10764c64c0f5dc27 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 1 Nov 2025 07:39:15 +0000
Subject: [PATCH] Add additional test cases to verify different base domains
 produce different shuffle orders

Added two more test cases with the same dataset (region 4) but different base domains to ensure the shuffle is truly deterministic and that different seeds produce different results.

Co-authored-by: kradalby <98431+kradalby@users.noreply.github.com>
---
 hscontrol/derp/derp_test.go | 68 +++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/hscontrol/derp/derp_test.go b/hscontrol/derp/derp_test.go
index 0a6b714f..91d605a6 100644
--- a/hscontrol/derp/derp_test.go
+++ b/hscontrol/derp/derp_test.go
@@ -169,6 +169,74 @@ func TestShuffleDERPMapDeterministic(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:       "same dataset with another base domain",
+			baseDomain: "another.example.com",
+			derpMap: &tailcfg.DERPMap{
+				Regions: map[int]*tailcfg.DERPRegion{
+					4: {
+						RegionID:   4,
+						RegionCode: "fra",
+						RegionName: "Frankfurt",
+						Nodes: []*tailcfg.DERPNode{
+							{Name: "4f", RegionID: 4, HostName: "derp4f.tailscale.com"},
+							{Name: "4g", RegionID: 4, HostName: "derp4g.tailscale.com"},
+							{Name: "4h", RegionID: 4, HostName: "derp4h.tailscale.com"},
+							{Name: "4i", RegionID: 4, HostName: "derp4i.tailscale.com"},
+						},
+					},
+				},
+			},
+			expected: &tailcfg.DERPMap{
+				Regions: map[int]*tailcfg.DERPRegion{
+					4: {
+						RegionID:   4,
+						RegionCode: "fra",
+						RegionName: "Frankfurt",
+						Nodes: []*tailcfg.DERPNode{
+							{Name: "4h", RegionID: 4, HostName: "derp4h.tailscale.com"},
+							{Name: "4f", RegionID: 4, HostName: "derp4f.tailscale.com"},
+							{Name: "4g", RegionID: 4, HostName: "derp4g.tailscale.com"},
+							{Name: "4i", RegionID: 4, HostName: "derp4i.tailscale.com"},
+						},
+					},
+				},
+			},
+		},
+		{
+			name:       "same dataset with yet another base domain",
+			baseDomain: "yetanother.example.com",
+			derpMap: &tailcfg.DERPMap{
+				Regions: map[int]*tailcfg.DERPRegion{
+					4: {
+						RegionID:   4,
+						RegionCode: "fra",
+						RegionName: "Frankfurt",
+						Nodes: []*tailcfg.DERPNode{
+							{Name: "4f", RegionID: 4, HostName: "derp4f.tailscale.com"},
+							{Name: "4g", RegionID: 4, HostName: "derp4g.tailscale.com"},
+							{Name: "4h", RegionID: 4, HostName: "derp4h.tailscale.com"},
+							{Name: "4i", RegionID: 4, HostName: "derp4i.tailscale.com"},
+						},
+					},
+				},
+			},
+			expected: &tailcfg.DERPMap{
+				Regions: map[int]*tailcfg.DERPRegion{
+					4: {
+						RegionID:   4,
+						RegionCode: "fra",
+						RegionName: "Frankfurt",
+						Nodes: []*tailcfg.DERPNode{
+							{Name: "4i", RegionID: 4, HostName: "derp4i.tailscale.com"},
+							{Name: "4h", RegionID: 4, HostName: "derp4h.tailscale.com"},
+							{Name: "4f", RegionID: 4, HostName: "derp4f.tailscale.com"},
+							{Name: "4g", RegionID: 4, HostName: "derp4g.tailscale.com"},
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for _, tt := range tests {