new file mode 100755
@@ -0,0 +1,59 @@
+#!/bin/sh
+#
+# Copyright (c) 2019 Denton Liu
+#
+
+test_description='ensure rebase fast-forwards commits when possible'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+ test_commit A &&
+ test_commit B &&
+ test_commit C &&
+ test_commit D &&
+ git checkout -t -b side
+'
+
+test_rebase_same_head() {
+ status="$1" &&
+ shift &&
+ test_expect_$status "git rebase $* with $changes is no-op" "
+ oldhead=\$(git rev-parse HEAD) &&
+ test_when_finished 'git reset --hard \$oldhead' &&
+ git rebase $* &&
+ newhead=\$(git rev-parse HEAD) &&
+ test_cmp_rev \$oldhead \$newhead
+ "
+}
+
+changes='no changes'
+test_rebase_same_head success
+test_rebase_same_head success master
+test_rebase_same_head success --onto B B
+test_rebase_same_head success --onto B... B
+test_rebase_same_head success --onto master... master
+
+test_expect_success 'add work to side' '
+ test_commit E
+'
+
+changes='our changes'
+test_rebase_same_head success
+test_rebase_same_head success master
+test_rebase_same_head success --onto B B
+test_rebase_same_head success --onto B... B
+test_rebase_same_head success --onto master... master
+
+test_expect_success 'add work to upstream' '
+ git checkout master &&
+ test_commit F &&
+ git checkout side
+'
+
+changes='our and their changes'
+test_rebase_same_head success --onto B B
+test_rebase_same_head success --onto B... B
+test_rebase_same_head failure --onto master... master
+
+test_done
When rebase is run on a branch that can be fast-forwarded, this should automatically be done. Create test to ensure this behavior happens. There is one case that currently does not pass. In the case where a feature and master have diverged, running "git rebase master... master" causes a full rebase to happen even though a fast-forward should happen. Mark this case as failure so we can fix it later. Signed-off-by: Denton Liu <liu.denton@gmail.com> --- t/t3432-rebase-fast-forward.sh | 59 ++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100755 t/t3432-rebase-fast-forward.sh