Add test for how we show a worktree that is inside the main work tree

We show this with a worktree icon (which is only shown when nerd fonts
are used, so turn these on), but also we strip the trailing `/` that
"git status" reports, so that it shows as a file rather than a directory
with a bogus file in it.

The reason for adding the test is that we are going to touch the logic
that determines whether an item in the Files panel is a linked worktree,
and this guards against regressing.

pkg/integration/tests/test_list.go

@@ -557,4 +557,5 @@ var tests = []*components.IntegrationTest{
 	worktree.SeparateWorkTreeConfig,
 	worktree.SymlinkIntoRepoSubdir,
 	worktree.WorktreeInRepo,
+	worktree.WorktreeInsideRepo,
 }

pkg/integration/tests/worktree/worktree_inside_repo.go

@@ -0,0 +1,28 @@
+package worktree
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var WorktreeInsideRepo = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "A worktree that lives inside the repo's working tree is shown as a single item in the files panel",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.GetUserConfig().Gui.NerdFontsVersion = "3"
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.NewBranch("mybranch")
+		shell.CreateFileAndAdd("README.md", "hello world")
+		shell.Commit("initial commit")
+		shell.AddWorktree("mybranch", "nested-worktree", "newbranch")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(
+				Equals("?? 󰌹 nested-worktree").IsSelected(),
+			)
+	},
+})