+test_expect_success 'set diff.wordregex option' '
+ git config diff.wordregex "[[:alnum:]]+"
+'
+
+cp expect.letter-runs-are-words expect
+
+test_expect_success 'command-line overrides config' '
+ word_diff --color-words="[a-z]+"
+'
+
+cp expect.non-whitespace-is-word expect
+
+test_expect_success '.gitattributes override config' '
+ word_diff --color-words
+'
+
+test_expect_success 'remove diff driver regex' '
+ git config --unset diff.testdriver.wordregex
+'
+
+cat > expect <<\EOF
+<WHITE>diff --git a/pre b/post<RESET>
+<WHITE>index 330b04f..5ed8eff 100644<RESET>
+<WHITE>--- a/pre<RESET>
+<WHITE>+++ b/post<RESET>
+<BROWN>@@ -1,3 +1,7 @@<RESET>
+h(4),<GREEN>hh[44<RESET>]
+<RESET>
+a = b + c<RESET>
+
+<GREEN>aa = a<RESET>
+
+<GREEN>aeff = aeff * ( aaa<RESET> )
+EOF
+
+test_expect_success 'use configured regex' '
+ word_diff --color-words
+'
+