migrate discard staged changes test

pkg/integration/tests/file/discard_staged_changes.go

@@ -0,0 +1,52 @@
+package file
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var DiscardStagedChanges = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Discarding staged changes",
+	ExtraCmdArgs: "",
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateFileAndAdd("fileToRemove", "original content")
+		shell.CreateFileAndAdd("file2", "original content")
+		shell.Commit("first commit")
+
+		shell.CreateFile("file3", "original content")
+		shell.UpdateFile("fileToRemove", "new content")
+		shell.UpdateFile("file2", "new content")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(
+				Contains(` M file2`).IsSelected(),
+				Contains(` M fileToRemove`),
+				Contains(`?? file3`),
+			).
+			SelectNextItem().
+			PressPrimaryAction().
+			Lines(
+				Contains(` M file2`),
+				Contains(`M  fileToRemove`).IsSelected(),
+				Contains(`?? file3`),
+			).
+			Press(keys.Files.ViewResetOptions)
+
+		t.ExpectPopup().Menu().Title(Equals("")).Select(Contains("discard staged changes")).Confirm()
+
+		// staged file has been removed
+		t.Views().Files().
+			Lines(
+				Contains(` M file2`),
+				Contains(`?? file3`).IsSelected(),
+			)
+
+		// the file should have the same content that it originally had, given that that was committed already
+		t.FileSystem().FileContainsContent("fileToRemove", Equals("original content"))
+	},
+})