diff --git a/src/float.rs b/src/float.rs
index 3094dd4..fa7eb6b 100644
--- a/src/float.rs
+++ b/src/float.rs
@@ -2083,6 +2083,6 @@ mod tests {
     fn realret() {
         use float::Float;
 
-        assert_eq!(Float::imag(0.5f64), 0.0f64);
+        assert_eq!(Float::arg(0.5f64), 0.0f64);
     }
 }