tests: add cmd_spec

spec/cmd_spec.lua

@@ -0,0 +1,59 @@
+---@diagnostic disable: invisible
+local cmd = require("lz.n.handler.cmd")
+local state = require("lz.n.state")
+local loader = require("lz.n.loader")
+local spy = require("luassert.spy")
+
+describe("cmd", function()
+    it("Command only loads plugin once and executes plugin command", function()
+        ---@type LzPlugin
+        local plugin = {
+            name = "foo",
+            cmd = { "Foo" },
+        }
+        local spy_load = spy.on(loader, "_load")
+        state.plugins[plugin.name] = plugin
+        cmd.add(plugin)
+        assert.is_not_nil(vim.cmd.Foo)
+        local counter = 0
+        local orig_load = loader._load
+        ---@diagnostic disable-next-line: duplicate-set-field
+        loader._load = function(...)
+            orig_load(...)
+            vim.api.nvim_create_user_command("Foo", function()
+                counter = counter + 1
+            end, {})
+        end
+        vim.cmd.Foo()
+        vim.cmd.Foo()
+        assert.spy(spy_load).called(1)
+        assert.same(2, counter)
+        loader._load = orig_load
+    end)
+    it("Multiple commands only load plugin once", function()
+        ---@param commands string[]
+        local function itt(commands)
+            local orig_load = loader._load
+            ---@diagnostic disable-next-line: duplicate-set-field
+            loader._load = function(...)
+                orig_load(...)
+                vim.api.nvim_create_user_command("Foo", function() end, {})
+                vim.api.nvim_create_user_command("Bar", function() end, {})
+            end
+            ---@type LzPlugin
+            local plugin = {
+                name = "foo",
+                cmd = commands,
+            }
+            local spy_load = spy.on(loader, "_load")
+            state.plugins[plugin.name] = plugin
+            cmd.add(plugin)
+            vim.cmd[commands[1]]()
+            vim.cmd[commands[2]]()
+            assert.spy(spy_load).called(1)
+            loader._load = orig_load
+        end
+        itt({ "Foo", "Bar" })
+        itt({ "Bar", "Foo" })
+    end)
+end)