Add new command "Checkout previous branch"

pkg/integration/tests/branch/checkout_previous_branch.go

@@ -0,0 +1,51 @@
+package branch
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var CheckoutPreviousBranch = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Checkout to the previous branch using the checkout previous branch functionality",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.
+			CreateNCommits(3).
+			NewBranch("previous-branch").
+			EmptyCommit("previous commit").
+			Checkout("master").
+			EmptyCommit("master commit")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Branches().
+			Focus().
+			Lines(
+				Contains("master").IsSelected(),
+				Contains("previous-branch"),
+			)
+
+		// Press the checkout previous branch key (should checkout previous-branch)
+		t.Views().Branches().
+			Press(keys.Branches.CheckoutPreviousBranch).
+			Lines(
+				Contains("previous-branch").IsSelected(),
+				Contains("master"),
+			)
+
+		// Verify we're on previous-branch
+		t.Git().CurrentBranchName("previous-branch")
+
+		// Press again to go back to master
+		t.Views().Branches().
+			Press(keys.Branches.CheckoutPreviousBranch).
+			Lines(
+				Contains("master").IsSelected(),
+				Contains("previous-branch"),
+			)
+
+		// Verify we're back on master
+		t.Git().CurrentBranchName("master")
+	},
+})

pkg/integration/tests/test_list.go

@@ -40,6 +40,7 @@ var tests = []*components.IntegrationTest{
 	bisect.Skip,
 	branch.CheckoutAutostash,
 	branch.CheckoutByName,
+	branch.CheckoutPreviousBranch,
 	branch.CreateTag,
 	branch.Delete,
 	branch.DeleteMultiple,