Add option to (un)set upstream for a local branch

pkg/gui/controllers/helpers/upstream_helper_test.go

@@ -0,0 +1,31 @@
+package helpers
+
+import (
+	"testing"
+
+	"github.com/jesseduffield/generics/slices"
+	"github.com/jesseduffield/lazygit/pkg/commands/models"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetSuggestedRemote(t *testing.T) {
+	cases := []struct {
+		remotes  []*models.Remote
+		expected string
+	}{
+		{mkRemoteList(), "origin"},
+		{mkRemoteList("upstream", "origin", "foo"), "origin"},
+		{mkRemoteList("upstream", "foo", "bar"), "upstream"},
+	}
+
+	for _, c := range cases {
+		result := getSuggestedRemote(c.remotes)
+		assert.EqualValues(t, c.expected, result)
+	}
+}
+
+func mkRemoteList(names ...string) []*models.Remote {
+	return slices.Map(names, func(name string) *models.Remote {
+		return &models.Remote{Name: name}
+	})
+}