Refactor how numbers are printed

src/value/number.rs

@@ -100,28 +100,47 @@ impl Display for Number {
         if self.val.is_negative() {
             f.write_char('-')?;
         }
-        write!(f, "{}", self.val.to_integer().abs())?;
+
+        let mut whole = self.val.to_integer().abs();
+        let mut dec = String::new();
+
         let mut frac = self.val.fract();
         if frac != BigRational::from_integer(BigInt::from(0)) {
-            f.write_char('.')?;
+            dec.write_char('.')?;
             for _ in 0..(PRECISION - 1) {
                 frac *= BigRational::from_integer(BigInt::from(10));
-                write!(f, "{}", frac.to_integer().abs())?;
+                write!(dec, "{}", frac.to_integer().abs())?;
                 frac = frac.fract();
                 if frac == BigRational::from_integer(BigInt::from(0)) {
                     break;
                 }
             }
             if frac != BigRational::from_integer(BigInt::from(0)) {
-                write!(
+                let f = (frac * BigRational::from_integer(BigInt::from(10)))
-                    f,
-                    "{}",
-                    (frac * BigRational::from_integer(BigInt::from(10)))
                     .round()
-                        .to_integer()
+                    .abs()
-                )?;
+                    .to_integer();
+                if f == BigInt::from(10) {
+                    loop {
+                        match dec.pop().unwrap() {
+                            '9' => continue,
+                            '.' => {
+                                whole += 1;
+                                break;
+                            }
+                            c => {
+                                dec.push_str(&(c.to_digit(10).unwrap() + 1).to_string());
+                                break;
                             }
                         }
+                    }
+                } else {
+                    write!(dec, "{}", f)?;
+                }
+            }
+        }
+        write!(f, "{}", whole)?;
+        write!(f, "{}", dec)?;
         Ok(())
     }
 }

tests/misc.rs

@@ -46,15 +46,3 @@ test!(
     "a {\n  color: red; ;\n}\n",
     "a {\n  color: red;\n}\n"
 );
-// these two precisiont tests only act like this in dart sass
-// these values are `1` for libsass
-test!(
-    precision_does_not_round_up,
-    "a {\n  color: 0.99999999991;\n}\n",
-    "a {\n  color: 0.9999999999;\n}\n"
-);
-test!(
-    precision_does_round_up,
-    "a {\n  color: 1.00000000009;\n}\n",
-    "a {\n  color: 1.0000000001;\n}\n"
-);

tests/number.rs

@@ -0,0 +1,52 @@
+#![cfg(test)]
+
+#[macro_use]
+mod macros;
+
+// this is `1` for libsass
+test!(
+    precision_does_not_round_up,
+    "a {\n  color: 0.99999999991;\n}\n",
+    "a {\n  color: 0.9999999999;\n}\n"
+);
+// this is `1` for libsass
+test!(
+    precision_does_round_up,
+    "a {\n  color: 1.00000000009;\n}\n",
+    "a {\n  color: 1.0000000001;\n}\n"
+);
+test!(
+    many_nines_becomes_one,
+    "a {\n  color: 0.9999999999999999;\n}\n",
+    "a {\n  color: 1;\n}\n"
+);
+test!(
+    many_nines_becomes_one_neg,
+    "a {\n  color: -0.9999999999999999;\n}\n",
+    "a {\n  color: -1;\n}\n"
+);
+test!(
+    negative_zero,
+    "a {\n  color: -0;\n}\n",
+    "a {\n  color: 0;\n}\n"
+);
+test!(
+    decimal_is_zero,
+    "a {\n  color: 1.0;\n}\n",
+    "a {\n  color: 1;\n}\n"
+);
+test!(many_nines_not_rounded, "a {\n  color: 0.999999;\n}\n");
+test!(positive_integer, "a {\n  color: 1;\n}\n");
+test!(negative_integer, "a {\n  color: -1;\n}\n");
+test!(
+    positive_float_no_leading_zero,
+    "a {\n  color: .1;\n}\n",
+    "a {\n  color: 0.1;\n}\n"
+);
+test!(
+    negative_float_no_leading_zero,
+    "a {\n  color: -.1;\n}\n",
+    "a {\n  color: -0.1;\n}\n"
+);
+test!(positive_float_leading_zero, "a {\n  color: 0.1;\n}\n");
+test!(negative_float_leading_zero, "a {\n  color: -0.1;\n}\n");

tests/values.rs

@@ -321,20 +321,6 @@ test!(
     "a {\n  color: 1 + foo();\n}\n",
     "a {\n  color: 1foo();\n}\n"
 );
-test!(positive_integer, "a {\n  color: 1;\n}\n");
-test!(negative_integer, "a {\n  color: -1;\n}\n");
-test!(
-    positive_float_no_leading_zero,
-    "a {\n  color: .1;\n}\n",
-    "a {\n  color: 0.1;\n}\n"
-);
-test!(
-    negative_float_no_leading_zero,
-    "a {\n  color: -.1;\n}\n",
-    "a {\n  color: -0.1;\n}\n"
-);
-test!(positive_float_leading_zero, "a {\n  color: 0.1;\n}\n");
-test!(negative_float_leading_zero, "a {\n  color: -0.1;\n}\n");
 test!(
     unitless_plus_null,
     "a {\n  color: 1 + null;\n}\n",