test: update tests to cover preserving highlight groups

tests/precognition/e2e_spec.lua

@@ -10,10 +10,10 @@ describe("e2e tests", function()
 
     it("auto commands are set", function()
         local autocmds = vim.api.nvim_get_autocmds({ group = "precognition" })
-        eq(4, vim.tbl_count(autocmds))
+        eq(5, vim.tbl_count(autocmds))
         precognition.peek()
         autocmds = vim.api.nvim_get_autocmds({ group = "precognition" })
-        eq(7, vim.tbl_count(autocmds))
+        eq(8, vim.tbl_count(autocmds))
     end)
 
     -- it("namespace is created", function()
@@ -285,4 +285,10 @@ describe("Gutter Priority", function()
         eq(1, vim.tbl_count(gutter_extmarks))
         eq("gg", gutter_extmarks[1][4].sign_text)
     end)
+
+    it("preserves highlight groups thgourh a colorscheme change", function()
+        vim.cmd.colorscheme("default")
+        local hl = vim.api.nvim_get_hl(0, { name = "PrecognitionHighlight" })
+        eq(false, vim.tbl_isempty(hl))
+    end)
 end)