2 files changed, 58 insertions, 0 deletions
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index dfcf3a0aaa..5de1d19075 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -616,4 +616,46 @@ test_expect_success 'diff -I<regex>: detect malformed regex' '
 	test_i18ngrep "invalid regex given to -I: " error
 '
 
+# check_prefix <patch> <src> <dst>
+# check only lines with paths to avoid dependency on exact oid/contents
+check_prefix () {
+	grep -E '^(diff|---|\+\+\+) ' "$1" >actual.paths &&
+	cat >expect <<-EOF &&
+	diff --git $2 $3
+	--- $2
+	+++ $3
+	EOF
+	test_cmp expect actual.paths
+}
+
+test_expect_success 'diff-files does not respect diff.noprefix' '
+	git -c diff.noprefix diff-files -p >actual &&
+	check_prefix actual a/file0 b/file0
+'
+
+test_expect_success 'diff-files respects --no-prefix' '
+	git diff-files -p --no-prefix >actual &&
+	check_prefix actual file0 file0
+'
+
+test_expect_success 'diff respects diff.noprefix' '
+	git -c diff.noprefix diff >actual &&
+	check_prefix actual file0 file0
+'
+
+test_expect_success 'diff --default-prefix overrides diff.noprefix' '
+	git -c diff.noprefix diff --default-prefix >actual &&
+	check_prefix actual a/file0 b/file0
+'
+
+test_expect_success 'diff respects diff.mnemonicprefix' '
+	git -c diff.mnemonicprefix diff >actual &&
+	check_prefix actual i/file0 w/file0
+'
+
+test_expect_success 'diff --default-prefix overrides diff.mnemonicprefix' '
+	git -c diff.mnemonicprefix diff --default-prefix >actual &&
+	check_prefix actual a/file0 b/file0
+'
+
 test_done
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index ffc7c60680..8c3d06622a 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -2396,4 +2396,20 @@ test_expect_success 'interdiff: solo-patch' '
 	test_cmp expect actual
 '
 
+test_expect_success 'format-patch does not respect diff.noprefix' '
+	git -c diff.noprefix format-patch -1 --stdout >actual &&
+	grep "^--- a/blorp" actual
+'
+
+test_expect_success 'format-patch respects format.noprefix' '
+	git -c format.noprefix format-patch -1 --stdout >actual &&
+	grep "^--- blorp" actual
+'
+
+test_expect_success 'format-patch --default-prefix overrides format.noprefix' '
+	git -c format.noprefix \
+		format-patch -1 --default-prefix --stdout >actual &&
+	grep "^--- a/blorp" actual
+'
+
 test_done