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-rw-r--r--spec/util_fsm_spec.lua250
1 files changed, 250 insertions, 0 deletions
diff --git a/spec/util_fsm_spec.lua b/spec/util_fsm_spec.lua
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+describe("util.fsm", function ()
+ local new_fsm = require "util.fsm".new;
+
+ do
+ local fsm = new_fsm({
+ transitions = {
+ { name = "melt", from = "solid", to = "liquid" };
+ { name = "freeze", from = "liquid", to = "solid" };
+ };
+ });
+
+ it("works", function ()
+ local water = fsm:init("liquid");
+ water:freeze();
+ assert.equal("solid", water.state);
+ water:melt();
+ assert.equal("liquid", water.state);
+ end);
+
+ it("does not allow invalid transitions", function ()
+ local water = fsm:init("liquid");
+ assert.has_errors(function ()
+ water:melt();
+ end, "Invalid state transition: liquid cannot melt");
+
+ water:freeze();
+ assert.equal("solid", water.state);
+
+ water:melt();
+ assert.equal("liquid", water.state);
+
+ assert.has_errors(function ()
+ water:melt();
+ end, "Invalid state transition: liquid cannot melt");
+ end);
+ end
+
+ it("notifies observers", function ()
+ local n = 0;
+ local has_become_solid = spy.new(function (transition)
+ assert.is_table(transition);
+ assert.equal("solid", transition.to);
+ assert.is_not_nil(transition.instance);
+ n = n + 1;
+ if n == 1 then
+ assert.is_nil(transition.from);
+ assert.is_nil(transition.from_attr);
+ elseif n == 2 then
+ assert.equal("liquid", transition.from);
+ assert.is_nil(transition.from_attr);
+ assert.equal("freeze", transition.name);
+ end
+ end);
+ local is_melting = spy.new(function (transition)
+ assert.is_table(transition);
+ assert.equal("melt", transition.name);
+ assert.is_not_nil(transition.instance);
+ end);
+ local fsm = new_fsm({
+ transitions = {
+ { name = "melt", from = "solid", to = "liquid" };
+ { name = "freeze", from = "liquid", to = "solid" };
+ };
+ state_handlers = {
+ solid = has_become_solid;
+ };
+
+ transition_handlers = {
+ melt = is_melting;
+ };
+ });
+
+ local water = fsm:init("liquid");
+ assert.spy(has_become_solid).was_not_called();
+
+ local ice = fsm:init("solid"); --luacheck: ignore 211/ice
+ assert.spy(has_become_solid).was_called(1);
+
+ water:freeze();
+
+ assert.spy(is_melting).was_not_called();
+ water:melt();
+ assert.spy(is_melting).was_called(1);
+ end);
+
+ local function test_machine(fsm_spec, expected_transitions, test_func)
+ fsm_spec.handlers = fsm_spec.handlers or {};
+ fsm_spec.handlers.transitioned = function (transition)
+ local expected_transition = table.remove(expected_transitions, 1);
+ assert.same(expected_transition, {
+ name = transition.name;
+ to = transition.to;
+ to_attr = transition.to_attr;
+ from = transition.from;
+ from_attr = transition.from_attr;
+ });
+ end;
+ local fsm = new_fsm(fsm_spec);
+ test_func(fsm);
+ assert.equal(0, #expected_transitions);
+ end
+
+
+ it("handles transitions with the same name", function ()
+ local expected_transitions = {
+ { name = nil , from = "none", to = "A" };
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "step", from = "C", to = "D" };
+ };
+
+ test_machine({
+ default_state = "none";
+ transitions = {
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "step", from = "C", to = "D" };
+ };
+ }, expected_transitions, function (fsm)
+ local i = fsm:init("A");
+ i:step(); -- B
+ i:step(); -- C
+ i:step(); -- D
+ assert.has_errors(function ()
+ i:step();
+ end, "Invalid state transition: D cannot step");
+ end);
+ end);
+
+ it("handles supports wildcard transitions", function ()
+ local expected_transitions = {
+ { name = nil , from = "none", to = "A" };
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "reset", from = "C", to = "A" };
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "step", from = "C", to = "D" };
+ };
+
+ test_machine({
+ default_state = "none";
+ transitions = {
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "step", from = "C", to = "D" };
+ { name = "reset", from = "*", to = "A" };
+ };
+ }, expected_transitions, function (fsm)
+ local i = fsm:init("A");
+ i:step(); -- B
+ i:step(); -- C
+ i:reset(); -- A
+ i:step(); -- B
+ i:step(); -- C
+ i:step(); -- D
+ assert.has_errors(function ()
+ i:step();
+ end, "Invalid state transition: D cannot step");
+ end);
+ end);
+
+ it("supports specifying multiple from states", function ()
+ local expected_transitions = {
+ { name = nil , from = "none", to = "A" };
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "reset", from = "C", to = "A" };
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "step", from = "C", to = "D" };
+ };
+
+ test_machine({
+ default_state = "none";
+ transitions = {
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "C" };
+ { name = "step", from = "C", to = "D" };
+ { name = "reset", from = {"B", "C", "D"}, to = "A" };
+ };
+ }, expected_transitions, function (fsm)
+ local i = fsm:init("A");
+ i:step(); -- B
+ i:step(); -- C
+ i:reset(); -- A
+ assert.has_errors(function ()
+ i:reset();
+ end, "Invalid state transition: A cannot reset");
+ i:step(); -- B
+ i:step(); -- C
+ i:step(); -- D
+ assert.has_errors(function ()
+ i:step();
+ end, "Invalid state transition: D cannot step");
+ end);
+ end);
+
+ it("handles transitions with the same start/end state", function ()
+ local expected_transitions = {
+ { name = nil , from = "none", to = "A" };
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "B" };
+ { name = "step", from = "B", to = "B" };
+ };
+
+ test_machine({
+ default_state = "none";
+ transitions = {
+ { name = "step", from = "A", to = "B" };
+ { name = "step", from = "B", to = "B" };
+ };
+ }, expected_transitions, function (fsm)
+ local i = fsm:init("A");
+ i:step(); -- B
+ i:step(); -- B
+ i:step(); -- B
+ end);
+ end);
+
+ it("can identify instances of a specific fsm", function ()
+ local fsm1 = new_fsm({ default_state = "a" });
+ local fsm2 = new_fsm({ default_state = "a" });
+
+ local i1 = fsm1:init();
+ local i2 = fsm2:init();
+
+ assert.truthy(fsm1:is_instance(i1));
+ assert.truthy(fsm2:is_instance(i2));
+
+ assert.falsy(fsm1:is_instance(i2));
+ assert.falsy(fsm2:is_instance(i1));
+ end);
+
+ it("errors when an invalid initial state is passed", function ()
+ local fsm1 = new_fsm({
+ transitions = {
+ { name = "", from = "A", to = "B" };
+ };
+ });
+
+ assert.has_no_errors(function ()
+ fsm1:init("A");
+ end);
+
+ assert.has_errors(function ()
+ fsm1:init("C");
+ end);
+ end);
+end);