eventable: Fix unhooking of handlers

matrix/eventable.lua

@@ -39,19 +39,23 @@ end)()
 
 local function do_hook(event_map, event, handler)
    log("hook:", event, handler)
-   if not handler then
-      event_map[event] = nil
-   else
+   if handler then
       if not event_map[event] then
          event_map[event] = {}
       end
       local handlers = event_map[event]
       handlers[#handlers + 1] = handler
+   else
+      return event_map[event]
    end
 end
 
 local function do_unhook(event_map, event, handler)
    log("unhook:", event, handler)
+   if handler == nil then
+      event_map[event] = nil
+      return
+   end
    local old_handlers = event_map[event]
    if old_handlers then
       local handlers = {}

spec/eventable_spec.lua

@@ -78,6 +78,42 @@ describe("matrix.eventable.functions()", function ()
       assert.spy(h1).was_called(2)
       assert.spy(h2).was_called(1)
    end)
+
+   it("allows unhooking all handlers at once", function ()
+      local fire, hook, unhook = assert(eventable.functions())
+
+      local h1 = spy.new(function () end)
+      local h2 = spy.new(function () end)
+      hook("foo", h1)
+      hook("foo", h2)
+      fire("foo")
+      assert.spy(h1).was_called(1)
+      assert.spy(h2).was_called(1)
+
+      unhook("foo")
+      fire("foo")
+      assert.spy(h1).was_called(1)
+      assert.spy(h2).was_called(1)
+   end)
+
+   it("allows retrieving the list of handlers", function ()
+      local fire, hook = assert(eventable.functions())
+      local h = function () end
+      hook("foo", h)
+      assert.same({ h }, hook("foo"))
+      hook("foo", h)
+      assert.same({ h, h }, hook("foo"))
+   end)
+
+   it("unhooks multiple instances of the same handler", function ()
+      local fire, hook, unhook = assert(eventable.functions())
+      local h = function () end
+      hook("foo", h)
+      hook("foo", h)
+      assert.same({ h, h }, hook("foo"))
+      unhook("foo", h)
+      assert.same({}, hook("foo"))
+   end)
 end)
 
 describe("matrix.eventable.object()", function ()