From ba98fa53780bf19266d7e5049fd7ec31eaad18bf Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Fri, 4 Nov 2022 11:15:04 +0100
Subject: Harden type 2 signal group API; add test for type 2 main signals

---
 advtrains_interlocking/signal_aspects.lua  |  17 +++--
 advtrains_interlocking/spec/type2_spec.lua | 103 +++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+), 5 deletions(-)
 create mode 100644 advtrains_interlocking/spec/type2_spec.lua

diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
index 37af7aa..65e970f 100644
--- a/advtrains_interlocking/signal_aspects.lua
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -9,13 +9,15 @@ local type2defs = {}
 local function register_type2(def)
 	local t = {type = 2}
 	local name = def.name
-	if type2defs[name] then
-		return error("Name " .. name .. " already used")
-	elseif type(name) ~= "string" then
+	if type(name) ~= "string" then
 		return error("Name is not a string")
+	elseif type2defs[name] then
+		return error(string.format("Attempt to redefine type 2 signal aspect group %q, previously defined in %s", name, type2defs[name].defined))
 	end
 	t.name = name
 
+	t.defined = debug.getinfo(2, "S").short_src or "[?]"
+
 	local label = def.label or name
 	if type(label) ~= "string" then
 		return error("Label is not a string")
@@ -54,7 +56,12 @@ end
 -- @return[1] The definition for the signal group (if present).
 -- @return[2] The nil constant (otherwise).
 local function get_type2_definition(name)
-	return type2defs[name]
+	local t = type2defs[name]
+	if t then
+		return table.copy(t)
+	else
+		return nil
+	end
 end
 
 --- Get the name of the distant aspect before the current aspect.
@@ -151,7 +158,7 @@ local function type1_to_type2main(asp, group, shift)
 	return t_main[math.max(1, idx-(shift or 0))].name
 end
 
---- Compare two signal aspect tables.
+--- Compare two type 1 signal aspect tables.
 -- @function equalp
 -- @param asp1 The first signal aspect table.
 -- @param asp2 The second signal aspect table.
diff --git a/advtrains_interlocking/spec/type2_spec.lua b/advtrains_interlocking/spec/type2_spec.lua
new file mode 100644
index 0000000..514f6aa
--- /dev/null
+++ b/advtrains_interlocking/spec/type2_spec.lua
@@ -0,0 +1,103 @@
+require "mineunit"
+mineunit("core")
+
+_G.advtrains = {
+	interlocking = {
+		aspects = sourcefile("signal_aspects"),
+	},
+	ndb = {
+		get_node = minetest.get_node,
+		swap_node = minetest.swap_node,
+	}
+}
+
+fixture("advtrains_helpers")
+sourcefile("database")
+sourcefile("signal_api")
+sourcefile("distant")
+sourcefile("signal_aspect_accessors")
+
+local A = advtrains.interlocking.aspects
+local D = advtrains.distant
+local I = advtrains.interlocking
+local N = advtrains.ndb
+
+local type2def = {
+	name = "foo",
+	main = {
+		{name = "proceed", main = -1},
+		{name = "caution"},
+		{name = "danger", main = 0},
+	},
+}
+
+local asps = {}
+for _, v in pairs(type2def.main) do
+	minetest.register_node("advtrains_interlocking:" .. v.name, {
+		advtrains = {
+			supported_aspects = {
+				type = 2,
+				group = "foo",
+			},
+			get_aspect = function() return v.name end,
+			set_aspect = function(pos, _, name)
+				N.swap_node(pos, {name = "advtrains_interlocking:" .. name})
+			end,
+		}
+	})
+	asps[v.name] = {
+		main = v.main,
+		type2group = "foo",
+		type2name = v.name,
+	}
+end
+
+local origin = vector.new(0, 0, 0)
+local dstpos = vector.new(0, 0, 1)
+
+world.layout {
+	{origin, "advtrains_interlocking:danger"},
+	{dstpos, "advtrains_interlocking:proceed"},
+}
+
+describe("type 2 signal group registration", function()
+	it("should work", function()
+		A.register_type2(type2def)
+		assert(A.get_type2_definition("foo"))
+	end)
+	it("should only be allowed once for the same group", function()
+		assert.has.errors(function() A.register_type2(type2def) end)
+	end)
+	it("should handle nonexistant groups", function()
+		assert.is_nil(A.get_type2_definition("something_else"))
+	end)
+end)
+
+describe("signal aspect conversion", function()
+	it("should work for converting from type 1 to type 2", function()
+		assert.equal("danger", A.type1_to_type2main({main = 0}, "foo"))
+		assert.equal("caution", A.type1_to_type2main({main = 6}, "foo"))
+		assert.equal("proceed", A.type1_to_type2main({}, "foo"))
+	end)
+	-- Type 2 -> type 1 conversion is tested with signal aspect accessors
+end)
+
+describe("type 2 signals", function()
+	it("should support distant signaling", function()
+		assert.equal("caution", A.get_type2_dst("foo", 3))
+		assert.equal("proceed", A.get_type2_dst("foo", "caution"))
+		assert.equal("proceed", A.get_type2_dst("foo", "proceed"))
+	end)
+	it("should work with accessors", function()
+		assert.same(asps.danger, I.signal_get_aspect(origin))
+		local newasp = {type2group = "foo", type2name = "proceed", main = 6}
+		I.signal_set_aspect(origin, newasp)
+		assert.same(newasp, I.signal_get_aspect(origin))
+	end)
+	it("should work with distant signaling", function()
+		assert.same(asps.proceed, I.signal_get_aspect(dstpos))
+		local dstasp = {type2group = "foo", type2name = "proceed", dst = 6, main = -1}
+		D.assign(origin, dstpos)
+		assert.same(dstasp, I.signal_get_aspect(dstpos))
+	end)
+end)
-- 
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