Use UpstreamBranch for opening pull requests

pkg/integration/tests/branch/open_pull_request_no_upstream.go

@@ -0,0 +1,25 @@
+package branch
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var OpenPullRequestNoUpstream = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Open up a pull request with a missing upstream branch",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo:    func(shell *Shell) {},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().
+			Branches().
+			Focus().
+			Press(keys.Branches.CreatePullRequest)
+
+		t.ExpectPopup().Alert().
+			Title(Equals("Error")).
+			Content(Contains("Cannot open a pull request for a branch with no upstream")).
+			Confirm()
+	},
+})