Add an integration test showing a problem with autosquash during normal rebase

For users who have the rebase.autoSquash git config set to true, any regular
rebase will squash fixups in addition to rebasing. Not good -- we'll fix that in
the next commit.

pkg/integration/tests/branch/rebase_does_not_autosquash.go

@@ -0,0 +1,56 @@
+package branch
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var RebaseDoesNotAutosquash = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Rebase a branch that has fixups onto another branch, and verify that the fixups are not squashed even if rebase.autoSquash is enabled globally.",
+	ExtraCmdArgs: "",
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.SetConfig("rebase.autoSquash", "true")
+
+		shell.
+			EmptyCommit("base").
+			NewBranch("my-branch").
+			Checkout("master").
+			EmptyCommit("master commit").
+			Checkout("my-branch").
+			EmptyCommit("branch commit").
+			EmptyCommit("fixup! branch commit")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().
+			Lines(
+				Contains("fixup! branch commit"),
+				Contains("branch commit"),
+				Contains("base"),
+			)
+
+		t.Views().Branches().
+			Focus().
+			Lines(
+				Contains("my-branch").IsSelected(),
+				Contains("master"),
+			).
+			SelectNextItem().
+			Press(keys.Branches.RebaseBranch)
+
+		t.ExpectPopup().Confirmation().
+			Title(Equals("Rebasing")).
+			Content(Contains("Are you sure you want to rebase 'my-branch' on top of 'master'?")).
+			Confirm()
+
+		t.Views().Commits().Lines(
+			/* Expected the fixup to be kept, but it's gone:
+			Contains("fixup! branch commit"),
+			*/
+			Contains("branch commit"),
+			Contains("master commit"),
+			Contains("base"),
+		)
+	},
+})

pkg/integration/tests/tests.go

@@ -37,6 +37,7 @@ var tests = []*components.IntegrationTest{
 	branch.Delete,
 	branch.Rebase,
 	branch.RebaseAndDrop,
+	branch.RebaseDoesNotAutosquash,
 	branch.Suggestions,
 	branch.Reset,
 	branch.DetachedHead,