Fix issue with zero duration

Author: devongovett

src/lib.rs

@@ -1319,6 +1319,7 @@ mod tests {
     minify_test(".foo { transition: width 2s 1s }", ".foo{transition:width 2s 1s}");
     minify_test(".foo { transition: width 2s ease 1s }", ".foo{transition:width 2s 1s}");
     minify_test(".foo { transition: ease-in 1s width 4s }", ".foo{transition:width 1s ease-in 4s}");
+    minify_test(".foo { transition: opacity 0s .6s }", ".foo{transition:opacity 0s .6s}");
     test(r#"
       .foo {
         transition-property: opacity;

src/properties/transition.rs

@@ -66,7 +66,7 @@ impl Parse for Transition {
 impl ToCss for Transition {
   fn to_css<W>(&self, dest: &mut Printer<W>) -> std::fmt::Result where W: std::fmt::Write {
     self.property.to_css(dest)?;
-    if self.duration != 0.0 {
+    if self.duration != 0.0 || self.delay != 0.0 {
       dest.write_char(' ')?;
       self.duration.to_css(dest)?;
     }

src/values/time.rs

@@ -43,7 +43,7 @@ impl ToCss for Time {
     // anything smaller is longer
     match self {
       Time::Seconds(s) => {
-        if *s < 0.1 {
+        if *s > 0.0 && *s < 0.1 {
           (*s * 1000.0).to_css(dest)?;
           dest.write_str("ms")
         } else {
@@ -52,7 +52,7 @@ impl ToCss for Time {
         }
       }
       Time::Milliseconds(ms) => {
-        if *ms >= 100.0 {
+        if *ms == 0.0 || *ms >= 100.0 {
           (*ms / 1000.0).to_css(dest)?;
           dest.write_str("s")
         } else {