Improve alpha/opacity function tests

src/value/number.rs

@@ -44,6 +44,10 @@ impl Display for Number {
                     break;
                 }
             }
+            if frac != BigRational::from_integer(BigInt::from(0)) {
+                write!(f, "{}", (frac * BigRational::from_integer(BigInt::from(10))).round().to_integer())?;
+            }
+
         }
         Ok(())
     }

tests/color.rs

@@ -49,5 +49,10 @@ test!(
 test!(
     alpha_function_4_hex,
     "a {\n  color: alpha(#0123);\n}\n",
-    "a {\n  color: .25;\n}\n"
+    "a {\n  color: 0.2;\n}\n"
+);
+test!(
+    alpha_function_named_color,
+    "a {\n  color: alpha(red);\n}\n",
+    "a {\n  color: 1;\n}\n"
 );