fix: exscpe test when passing it to vim syntax match

This was causing an issue an invalid regex. Now we are escapeing the
text to make it a valid regex.

There is also a small improvement where we no longer try and highlight
matched words if the "text" is empty.

Ref: #26

lua/ivy/controller.lua

@@ -34,7 +34,12 @@ controller.update = function(text)
   vim.schedule(function()
     window.set_items(controller.items(text))
     vim.cmd "syntax clear IvyMatch"
-    vim.cmd("syntax match IvyMatch '[(" .. text .. ")]'")
+    if #text > 0 then
+      -- Escape characters so they do not throw an error when vim tries to use
+      -- the "text" as a regex
+      local escaped_text = string.gsub(text, "([-/])", "\\%1")
+      vim.cmd("syntax match IvyMatch '[" .. escaped_text .. "]'")
+    end
   end)
 end
 

lua/ivy/controller_test.lua

@@ -0,0 +1,51 @@
+local vim_mock = require "ivy.vim_mock"
+local window = require "ivy.window"
+local controller = require "ivy.controller"
+
+-- The number of the mock buffer where all the test completions gets put
+local buffer_number = 10
+
+before_each(function()
+  vim_mock.reset()
+  window.initialize()
+end)
+
+after_each(function()
+  controller.destroy()
+end)
+
+it("will run", function(t)
+  controller.run("Testing", function()
+    return { { content = "Some content" } }
+  end, function()
+    return {}
+  end)
+
+  local lines = vim_mock.get_lines()
+  local completion_lines = lines[buffer_number]
+
+  t.assert_equal(#completion_lines, 1)
+  t.assert_equal(completion_lines[1], "Some content")
+end)
+
+it("will not try and highlight the buffer if there is nothing to highlight", function(t)
+  controller.items = function()
+    return { { content = "Hello" } }
+  end
+
+  controller.update ""
+  local commands = vim_mock.get_commands()
+  t.assert_equal(#commands, 1)
+end)
+
+it("will escape a - when passing it to be highlighted", function(t)
+  controller.items = function()
+    return { { content = "Hello" } }
+  end
+
+  controller.update "some-file"
+  local commands = vim_mock.get_commands()
+  local syntax_command = commands[2]
+
+  t.assert_equal("syntax match IvyMatch '[some\\-file]'", syntax_command)
+end)