diff --git a/tests/color_util.c b/tests/color_util.c
index da5eb5a3..fc406d87 100644
--- a/tests/color_util.c
+++ b/tests/color_util.c
@@ -257,7 +257,7 @@ a8r8g8b8_to_float(uint32_t v)
 	return cf;
 }
 
-static struct color_float
+struct color_float
 color_float_apply_curve(enum transfer_fn fn, struct color_float c)
 {
 	unsigned i;
diff --git a/tests/color_util.h b/tests/color_util.h
index fab42440..a5003fa8 100644
--- a/tests/color_util.h
+++ b/tests/color_util.h
@@ -111,6 +111,9 @@ process_pixel_using_pipeline(enum transfer_fn pre_curve,
 struct color_float
 color_float_unpremult(struct color_float in);
 
+struct color_float
+color_float_apply_curve(enum transfer_fn fn, struct color_float c);
+
 struct color_float
 color_float_apply_matrix(const struct lcmsMAT3 *mat, struct color_float c);