diff --git a/t/t7609-merge-co-error-msgs.sh b/t/t7609-merge-co-error-msgs.sh
new file mode 100755
index 00000000000..1a109b41dc6
--- /dev/null
+++ b/t/t7609-merge-co-error-msgs.sh
@@ -0,0 +1,125 @@
+#!/bin/sh
+
+test_description='unpack-trees error messages'
+
+. ./test-lib.sh
+
+
+test_expect_success 'setup' '
+	echo one >one &&
+	git add one &&
+	git commit -a -m First &&
+
+	git checkout -b branch &&
+	echo two >two &&
+	echo three >three &&
+	echo four >four &&
+	echo five >five &&
+	git add two three four five &&
+	git commit -m Second &&
+
+	git checkout master &&
+	echo other >two &&
+	echo other >three &&
+	echo other >four &&
+	echo other >five
+'
+
+cat >expect <<\EOF
+error: The following untracked working tree files would be overwritten by merge:
+	two
+	three
+	four
+	five
+Please move or remove them before you can merge.
+EOF
+
+test_expect_success 'untracked files overwritten by merge' '
+	test_must_fail git merge branch 2>out &&
+	test_cmp out expect
+'
+
+cat >expect <<\EOF
+error: Your local changes to the following files would be overwritten by merge:
+	two
+	three
+	four
+Please, commit your changes or stash them before you can merge.
+error: The following untracked working tree files would be overwritten by merge:
+	five
+Please move or remove them before you can merge.
+EOF
+
+test_expect_success 'untracked files or local changes ovewritten by merge' '
+	git add two &&
+	git add three &&
+	git add four &&
+	test_must_fail git merge branch 2>out &&
+	test_cmp out expect
+'
+
+cat >expect <<\EOF
+error: Your local changes to the following files would be overwritten by checkout:
+	rep/two
+	rep/one
+Please, commit your changes or stash them before you can switch branches.
+EOF
+
+test_expect_success 'cannot switch branches because of local changes' '
+	git add five &&
+	mkdir rep &&
+	echo one >rep/one &&
+	echo two >rep/two &&
+	git add rep/one rep/two &&
+	git commit -m Fourth &&
+	git checkout master &&
+	echo uno >rep/one &&
+	echo dos >rep/two &&
+	test_must_fail git checkout branch 2>out &&
+	test_cmp out expect
+'
+
+cat >expect <<\EOF
+error: Your local changes to the following files would be overwritten by checkout:
+	rep/two
+	rep/one
+Please, commit your changes or stash them before you can switch branches.
+EOF
+
+test_expect_success 'not uptodate file porcelain checkout error' '
+	git add rep/one rep/two &&
+	test_must_fail git checkout branch 2>out &&
+	test_cmp out expect
+'
+
+cat >expect <<\EOF
+error: Updating the following directories would lose untracked files in it:
+	rep2
+	rep
+
+EOF
+
+test_expect_success 'not_uptodate_dir porcelain checkout error' '
+	git init uptodate &&
+	cd uptodate &&
+	mkdir rep &&
+	mkdir rep2 &&
+	touch rep/foo &&
+	touch rep2/foo &&
+	git add rep/foo rep2/foo &&
+	git commit -m init &&
+	git checkout -b branch &&
+	git rm rep -r &&
+	git rm rep2 -r &&
+	>rep &&
+	>rep2 &&
+	git add rep rep2&&
+	git commit -m "added test as a file" &&
+	git checkout master &&
+	>rep/untracked-file &&
+	>rep2/untracked-file &&
+	test_must_fail git checkout branch 2>out &&
+	test_cmp out ../expect
+'
+
+test_done