Add command "Rebase onto base branch" to rebase menu

pkg/integration/tests/branch/rebase_onto_base_branch.go

@@ -0,0 +1,53 @@
+package branch
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var RebaseOntoBaseBranch = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Rebase the current branch onto its base branch",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.UserConfig.Gui.ShowDivergenceFromBaseBranch = "arrowAndNumber"
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.
+			EmptyCommit("master 1").
+			EmptyCommit("master 2").
+			EmptyCommit("master 3").
+			NewBranchFrom("feature", "master^").
+			EmptyCommit("feature 1").
+			EmptyCommit("feature 2")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().Lines(
+			Contains("feature 2"),
+			Contains("feature 1"),
+			Contains("master 2"),
+			Contains("master 1"),
+		)
+
+		t.Views().Branches().
+			Focus().
+			Lines(
+				Contains("feature ↓1").IsSelected(),
+				Contains("master"),
+			).
+			Press(keys.Branches.RebaseBranch)
+
+		t.ExpectPopup().Menu().
+			Title(Equals("Rebase 'feature'")).
+			Select(Contains("Rebase onto base branch (master)")).
+			Confirm()
+
+		t.Views().Commits().Lines(
+			Contains("feature 2"),
+			Contains("feature 1"),
+			Contains("master 3"),
+			Contains("master 2"),
+			Contains("master 1"),
+		)
+	},
+})