}
'
+test_expect_success '--check --exit-code returns 0 for no difference' '
+
+ git diff --check --exit-code
+
+'
+
+test_expect_success '--check --exit-code returns 1 for a clean difference' '
+
+ echo "good" > a &&
+ git diff --check --exit-code
+ test $? = 1
+
+'
+
+test_expect_success '--check --exit-code returns 3 for a dirty difference' '
+
+ echo "bad " >> a &&
+ git diff --check --exit-code
+ test $? = 3
+
+'
+
+test_expect_success '--check with --no-pager returns 2 for dirty difference' '
+
+ git --no-pager diff --check
+ test $? = 2
+
+'
+
test_done