From 0e2242f6d62d6d49bf8a2d1860a41273c1fdfa0d Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Mon, 6 May 2013 21:51:48 +1000
Subject: [PATCH] Add assert_approx_eq! macro

---
 src/libcore/num/f32.rs                        | 139 ++++++++---------
 src/libcore/num/f64.rs                        | 140 ++++++++----------
 src/libcore/num/float.rs                      | 139 ++++++++---------
 src/libsyntax/ext/expand.rs                   |  36 +++++
 .../assert-approx-eq-eps-macro-fail.rs        |  14 ++
 .../run-fail/assert-approx-eq-macro-fail.rs   |  14 ++
 .../assert-approx-eq-macro-success.rs         |  16 ++
 7 files changed, 275 insertions(+), 223 deletions(-)
 create mode 100644 src/test/run-fail/assert-approx-eq-eps-macro-fail.rs
 create mode 100644 src/test/run-fail/assert-approx-eq-macro-fail.rs
 create mode 100644 src/test/run-pass/assert-approx-eq-macro-success.rs

diff --git a/src/libcore/num/f32.rs b/src/libcore/num/f32.rs
index feeb2c3f83605..7c13f136a80f2 100644
--- a/src/libcore/num/f32.rs
+++ b/src/libcore/num/f32.rs
@@ -826,15 +826,6 @@ mod tests {
     use super::*;
     use prelude::*;
 
-    macro_rules! assert_fuzzy_eq(
-        ($a:expr, $b:expr) => ({
-            let a = $a, b = $b;
-            if !((a - b).abs() < 1.0e-6) {
-                fail!(fmt!("The values were not approximately equal. Found: %? and %?", a, b));
-            }
-        })
-    )
-
     #[test]
     fn test_num() {
         num::test_num(10f32, 2f32);
@@ -864,91 +855,91 @@ mod tests {
 
     #[test]
     fn test_floor() {
-        assert_fuzzy_eq!(1.0f32.floor(), 1.0f32);
-        assert_fuzzy_eq!(1.3f32.floor(), 1.0f32);
-        assert_fuzzy_eq!(1.5f32.floor(), 1.0f32);
-        assert_fuzzy_eq!(1.7f32.floor(), 1.0f32);
-        assert_fuzzy_eq!(0.0f32.floor(), 0.0f32);
-        assert_fuzzy_eq!((-0.0f32).floor(), -0.0f32);
-        assert_fuzzy_eq!((-1.0f32).floor(), -1.0f32);
-        assert_fuzzy_eq!((-1.3f32).floor(), -2.0f32);
-        assert_fuzzy_eq!((-1.5f32).floor(), -2.0f32);
-        assert_fuzzy_eq!((-1.7f32).floor(), -2.0f32);
+        assert_approx_eq!(1.0f32.floor(), 1.0f32);
+        assert_approx_eq!(1.3f32.floor(), 1.0f32);
+        assert_approx_eq!(1.5f32.floor(), 1.0f32);
+        assert_approx_eq!(1.7f32.floor(), 1.0f32);
+        assert_approx_eq!(0.0f32.floor(), 0.0f32);
+        assert_approx_eq!((-0.0f32).floor(), -0.0f32);
+        assert_approx_eq!((-1.0f32).floor(), -1.0f32);
+        assert_approx_eq!((-1.3f32).floor(), -2.0f32);
+        assert_approx_eq!((-1.5f32).floor(), -2.0f32);
+        assert_approx_eq!((-1.7f32).floor(), -2.0f32);
     }
 
     #[test]
     fn test_ceil() {
-        assert_fuzzy_eq!(1.0f32.ceil(), 1.0f32);
-        assert_fuzzy_eq!(1.3f32.ceil(), 2.0f32);
-        assert_fuzzy_eq!(1.5f32.ceil(), 2.0f32);
-        assert_fuzzy_eq!(1.7f32.ceil(), 2.0f32);
-        assert_fuzzy_eq!(0.0f32.ceil(), 0.0f32);
-        assert_fuzzy_eq!((-0.0f32).ceil(), -0.0f32);
-        assert_fuzzy_eq!((-1.0f32).ceil(), -1.0f32);
-        assert_fuzzy_eq!((-1.3f32).ceil(), -1.0f32);
-        assert_fuzzy_eq!((-1.5f32).ceil(), -1.0f32);
-        assert_fuzzy_eq!((-1.7f32).ceil(), -1.0f32);
+        assert_approx_eq!(1.0f32.ceil(), 1.0f32);
+        assert_approx_eq!(1.3f32.ceil(), 2.0f32);
+        assert_approx_eq!(1.5f32.ceil(), 2.0f32);
+        assert_approx_eq!(1.7f32.ceil(), 2.0f32);
+        assert_approx_eq!(0.0f32.ceil(), 0.0f32);
+        assert_approx_eq!((-0.0f32).ceil(), -0.0f32);
+        assert_approx_eq!((-1.0f32).ceil(), -1.0f32);
+        assert_approx_eq!((-1.3f32).ceil(), -1.0f32);
+        assert_approx_eq!((-1.5f32).ceil(), -1.0f32);
+        assert_approx_eq!((-1.7f32).ceil(), -1.0f32);
     }
 
     #[test]
     fn test_round() {
-        assert_fuzzy_eq!(1.0f32.round(), 1.0f32);
-        assert_fuzzy_eq!(1.3f32.round(), 1.0f32);
-        assert_fuzzy_eq!(1.5f32.round(), 2.0f32);
-        assert_fuzzy_eq!(1.7f32.round(), 2.0f32);
-        assert_fuzzy_eq!(0.0f32.round(), 0.0f32);
-        assert_fuzzy_eq!((-0.0f32).round(), -0.0f32);
-        assert_fuzzy_eq!((-1.0f32).round(), -1.0f32);
-        assert_fuzzy_eq!((-1.3f32).round(), -1.0f32);
-        assert_fuzzy_eq!((-1.5f32).round(), -2.0f32);
-        assert_fuzzy_eq!((-1.7f32).round(), -2.0f32);
+        assert_approx_eq!(1.0f32.round(), 1.0f32);
+        assert_approx_eq!(1.3f32.round(), 1.0f32);
+        assert_approx_eq!(1.5f32.round(), 2.0f32);
+        assert_approx_eq!(1.7f32.round(), 2.0f32);
+        assert_approx_eq!(0.0f32.round(), 0.0f32);
+        assert_approx_eq!((-0.0f32).round(), -0.0f32);
+        assert_approx_eq!((-1.0f32).round(), -1.0f32);
+        assert_approx_eq!((-1.3f32).round(), -1.0f32);
+        assert_approx_eq!((-1.5f32).round(), -2.0f32);
+        assert_approx_eq!((-1.7f32).round(), -2.0f32);
     }
 
     #[test]
     fn test_trunc() {
-        assert_fuzzy_eq!(1.0f32.trunc(), 1.0f32);
-        assert_fuzzy_eq!(1.3f32.trunc(), 1.0f32);
-        assert_fuzzy_eq!(1.5f32.trunc(), 1.0f32);
-        assert_fuzzy_eq!(1.7f32.trunc(), 1.0f32);
-        assert_fuzzy_eq!(0.0f32.trunc(), 0.0f32);
-        assert_fuzzy_eq!((-0.0f32).trunc(), -0.0f32);
-        assert_fuzzy_eq!((-1.0f32).trunc(), -1.0f32);
-        assert_fuzzy_eq!((-1.3f32).trunc(), -1.0f32);
-        assert_fuzzy_eq!((-1.5f32).trunc(), -1.0f32);
-        assert_fuzzy_eq!((-1.7f32).trunc(), -1.0f32);
+        assert_approx_eq!(1.0f32.trunc(), 1.0f32);
+        assert_approx_eq!(1.3f32.trunc(), 1.0f32);
+        assert_approx_eq!(1.5f32.trunc(), 1.0f32);
+        assert_approx_eq!(1.7f32.trunc(), 1.0f32);
+        assert_approx_eq!(0.0f32.trunc(), 0.0f32);
+        assert_approx_eq!((-0.0f32).trunc(), -0.0f32);
+        assert_approx_eq!((-1.0f32).trunc(), -1.0f32);
+        assert_approx_eq!((-1.3f32).trunc(), -1.0f32);
+        assert_approx_eq!((-1.5f32).trunc(), -1.0f32);
+        assert_approx_eq!((-1.7f32).trunc(), -1.0f32);
     }
 
     #[test]
     fn test_fract() {
-        assert_fuzzy_eq!(1.0f32.fract(), 0.0f32);
-        assert_fuzzy_eq!(1.3f32.fract(), 0.3f32);
-        assert_fuzzy_eq!(1.5f32.fract(), 0.5f32);
-        assert_fuzzy_eq!(1.7f32.fract(), 0.7f32);
-        assert_fuzzy_eq!(0.0f32.fract(), 0.0f32);
-        assert_fuzzy_eq!((-0.0f32).fract(), -0.0f32);
-        assert_fuzzy_eq!((-1.0f32).fract(), -0.0f32);
-        assert_fuzzy_eq!((-1.3f32).fract(), -0.3f32);
-        assert_fuzzy_eq!((-1.5f32).fract(), -0.5f32);
-        assert_fuzzy_eq!((-1.7f32).fract(), -0.7f32);
+        assert_approx_eq!(1.0f32.fract(), 0.0f32);
+        assert_approx_eq!(1.3f32.fract(), 0.3f32);
+        assert_approx_eq!(1.5f32.fract(), 0.5f32);
+        assert_approx_eq!(1.7f32.fract(), 0.7f32);
+        assert_approx_eq!(0.0f32.fract(), 0.0f32);
+        assert_approx_eq!((-0.0f32).fract(), -0.0f32);
+        assert_approx_eq!((-1.0f32).fract(), -0.0f32);
+        assert_approx_eq!((-1.3f32).fract(), -0.3f32);
+        assert_approx_eq!((-1.5f32).fract(), -0.5f32);
+        assert_approx_eq!((-1.7f32).fract(), -0.7f32);
     }
 
     #[test]
     fn test_real_consts() {
-        assert_fuzzy_eq!(Real::two_pi::<f32>(), 2f32 * Real::pi::<f32>());
-        assert_fuzzy_eq!(Real::frac_pi_2::<f32>(), Real::pi::<f32>() / 2f32);
-        assert_fuzzy_eq!(Real::frac_pi_3::<f32>(), Real::pi::<f32>() / 3f32);
-        assert_fuzzy_eq!(Real::frac_pi_4::<f32>(), Real::pi::<f32>() / 4f32);
-        assert_fuzzy_eq!(Real::frac_pi_6::<f32>(), Real::pi::<f32>() / 6f32);
-        assert_fuzzy_eq!(Real::frac_pi_8::<f32>(), Real::pi::<f32>() / 8f32);
-        assert_fuzzy_eq!(Real::frac_1_pi::<f32>(), 1f32 / Real::pi::<f32>());
-        assert_fuzzy_eq!(Real::frac_2_pi::<f32>(), 2f32 / Real::pi::<f32>());
-        assert_fuzzy_eq!(Real::frac_2_sqrtpi::<f32>(), 2f32 / Real::pi::<f32>().sqrt());
-        assert_fuzzy_eq!(Real::sqrt2::<f32>(), 2f32.sqrt());
-        assert_fuzzy_eq!(Real::frac_1_sqrt2::<f32>(), 1f32 / 2f32.sqrt());
-        assert_fuzzy_eq!(Real::log2_e::<f32>(), Real::e::<f32>().log2());
-        assert_fuzzy_eq!(Real::log10_e::<f32>(), Real::e::<f32>().log10());
-        assert_fuzzy_eq!(Real::log_2::<f32>(), 2f32.log());
-        assert_fuzzy_eq!(Real::log_10::<f32>(), 10f32.log());
+        assert_approx_eq!(Real::two_pi::<f32>(), 2f32 * Real::pi::<f32>());
+        assert_approx_eq!(Real::frac_pi_2::<f32>(), Real::pi::<f32>() / 2f32);
+        assert_approx_eq!(Real::frac_pi_3::<f32>(), Real::pi::<f32>() / 3f32);
+        assert_approx_eq!(Real::frac_pi_4::<f32>(), Real::pi::<f32>() / 4f32);
+        assert_approx_eq!(Real::frac_pi_6::<f32>(), Real::pi::<f32>() / 6f32);
+        assert_approx_eq!(Real::frac_pi_8::<f32>(), Real::pi::<f32>() / 8f32);
+        assert_approx_eq!(Real::frac_1_pi::<f32>(), 1f32 / Real::pi::<f32>());
+        assert_approx_eq!(Real::frac_2_pi::<f32>(), 2f32 / Real::pi::<f32>());
+        assert_approx_eq!(Real::frac_2_sqrtpi::<f32>(), 2f32 / Real::pi::<f32>().sqrt());
+        assert_approx_eq!(Real::sqrt2::<f32>(), 2f32.sqrt());
+        assert_approx_eq!(Real::frac_1_sqrt2::<f32>(), 1f32 / 2f32.sqrt());
+        assert_approx_eq!(Real::log2_e::<f32>(), Real::e::<f32>().log2());
+        assert_approx_eq!(Real::log10_e::<f32>(), Real::e::<f32>().log10());
+        assert_approx_eq!(Real::log_2::<f32>(), 2f32.log());
+        assert_approx_eq!(Real::log_10::<f32>(), 10f32.log());
     }
 
     #[test]
diff --git a/src/libcore/num/f64.rs b/src/libcore/num/f64.rs
index 08f9c341188ad..e5f10c23ecd87 100644
--- a/src/libcore/num/f64.rs
+++ b/src/libcore/num/f64.rs
@@ -869,16 +869,6 @@ mod tests {
     use super::*;
     use prelude::*;
 
-    macro_rules! assert_fuzzy_eq(
-        ($a:expr, $b:expr) => ({
-            let a = $a, b = $b;
-            if !((a - b).abs() < 1.0e-6) {
-                fail!(fmt!("The values were not approximately equal. \
-                            Found: %? and expected %?", a, b));
-            }
-        })
-    )
-
     #[test]
     fn test_num() {
         num::test_num(10f64, 2f64);
@@ -912,91 +902,91 @@ mod tests {
 
     #[test]
     fn test_floor() {
-        assert_fuzzy_eq!(1.0f64.floor(), 1.0f64);
-        assert_fuzzy_eq!(1.3f64.floor(), 1.0f64);
-        assert_fuzzy_eq!(1.5f64.floor(), 1.0f64);
-        assert_fuzzy_eq!(1.7f64.floor(), 1.0f64);
-        assert_fuzzy_eq!(0.0f64.floor(), 0.0f64);
-        assert_fuzzy_eq!((-0.0f64).floor(), -0.0f64);
-        assert_fuzzy_eq!((-1.0f64).floor(), -1.0f64);
-        assert_fuzzy_eq!((-1.3f64).floor(), -2.0f64);
-        assert_fuzzy_eq!((-1.5f64).floor(), -2.0f64);
-        assert_fuzzy_eq!((-1.7f64).floor(), -2.0f64);
+        assert_approx_eq!(1.0f64.floor(), 1.0f64);
+        assert_approx_eq!(1.3f64.floor(), 1.0f64);
+        assert_approx_eq!(1.5f64.floor(), 1.0f64);
+        assert_approx_eq!(1.7f64.floor(), 1.0f64);
+        assert_approx_eq!(0.0f64.floor(), 0.0f64);
+        assert_approx_eq!((-0.0f64).floor(), -0.0f64);
+        assert_approx_eq!((-1.0f64).floor(), -1.0f64);
+        assert_approx_eq!((-1.3f64).floor(), -2.0f64);
+        assert_approx_eq!((-1.5f64).floor(), -2.0f64);
+        assert_approx_eq!((-1.7f64).floor(), -2.0f64);
     }
 
     #[test]
     fn test_ceil() {
-        assert_fuzzy_eq!(1.0f64.ceil(), 1.0f64);
-        assert_fuzzy_eq!(1.3f64.ceil(), 2.0f64);
-        assert_fuzzy_eq!(1.5f64.ceil(), 2.0f64);
-        assert_fuzzy_eq!(1.7f64.ceil(), 2.0f64);
-        assert_fuzzy_eq!(0.0f64.ceil(), 0.0f64);
-        assert_fuzzy_eq!((-0.0f64).ceil(), -0.0f64);
-        assert_fuzzy_eq!((-1.0f64).ceil(), -1.0f64);
-        assert_fuzzy_eq!((-1.3f64).ceil(), -1.0f64);
-        assert_fuzzy_eq!((-1.5f64).ceil(), -1.0f64);
-        assert_fuzzy_eq!((-1.7f64).ceil(), -1.0f64);
+        assert_approx_eq!(1.0f64.ceil(), 1.0f64);
+        assert_approx_eq!(1.3f64.ceil(), 2.0f64);
+        assert_approx_eq!(1.5f64.ceil(), 2.0f64);
+        assert_approx_eq!(1.7f64.ceil(), 2.0f64);
+        assert_approx_eq!(0.0f64.ceil(), 0.0f64);
+        assert_approx_eq!((-0.0f64).ceil(), -0.0f64);
+        assert_approx_eq!((-1.0f64).ceil(), -1.0f64);
+        assert_approx_eq!((-1.3f64).ceil(), -1.0f64);
+        assert_approx_eq!((-1.5f64).ceil(), -1.0f64);
+        assert_approx_eq!((-1.7f64).ceil(), -1.0f64);
     }
 
     #[test]
     fn test_round() {
-        assert_fuzzy_eq!(1.0f64.round(), 1.0f64);
-        assert_fuzzy_eq!(1.3f64.round(), 1.0f64);
-        assert_fuzzy_eq!(1.5f64.round(), 2.0f64);
-        assert_fuzzy_eq!(1.7f64.round(), 2.0f64);
-        assert_fuzzy_eq!(0.0f64.round(), 0.0f64);
-        assert_fuzzy_eq!((-0.0f64).round(), -0.0f64);
-        assert_fuzzy_eq!((-1.0f64).round(), -1.0f64);
-        assert_fuzzy_eq!((-1.3f64).round(), -1.0f64);
-        assert_fuzzy_eq!((-1.5f64).round(), -2.0f64);
-        assert_fuzzy_eq!((-1.7f64).round(), -2.0f64);
+        assert_approx_eq!(1.0f64.round(), 1.0f64);
+        assert_approx_eq!(1.3f64.round(), 1.0f64);
+        assert_approx_eq!(1.5f64.round(), 2.0f64);
+        assert_approx_eq!(1.7f64.round(), 2.0f64);
+        assert_approx_eq!(0.0f64.round(), 0.0f64);
+        assert_approx_eq!((-0.0f64).round(), -0.0f64);
+        assert_approx_eq!((-1.0f64).round(), -1.0f64);
+        assert_approx_eq!((-1.3f64).round(), -1.0f64);
+        assert_approx_eq!((-1.5f64).round(), -2.0f64);
+        assert_approx_eq!((-1.7f64).round(), -2.0f64);
     }
 
     #[test]
     fn test_trunc() {
-        assert_fuzzy_eq!(1.0f64.trunc(), 1.0f64);
-        assert_fuzzy_eq!(1.3f64.trunc(), 1.0f64);
-        assert_fuzzy_eq!(1.5f64.trunc(), 1.0f64);
-        assert_fuzzy_eq!(1.7f64.trunc(), 1.0f64);
-        assert_fuzzy_eq!(0.0f64.trunc(), 0.0f64);
-        assert_fuzzy_eq!((-0.0f64).trunc(), -0.0f64);
-        assert_fuzzy_eq!((-1.0f64).trunc(), -1.0f64);
-        assert_fuzzy_eq!((-1.3f64).trunc(), -1.0f64);
-        assert_fuzzy_eq!((-1.5f64).trunc(), -1.0f64);
-        assert_fuzzy_eq!((-1.7f64).trunc(), -1.0f64);
+        assert_approx_eq!(1.0f64.trunc(), 1.0f64);
+        assert_approx_eq!(1.3f64.trunc(), 1.0f64);
+        assert_approx_eq!(1.5f64.trunc(), 1.0f64);
+        assert_approx_eq!(1.7f64.trunc(), 1.0f64);
+        assert_approx_eq!(0.0f64.trunc(), 0.0f64);
+        assert_approx_eq!((-0.0f64).trunc(), -0.0f64);
+        assert_approx_eq!((-1.0f64).trunc(), -1.0f64);
+        assert_approx_eq!((-1.3f64).trunc(), -1.0f64);
+        assert_approx_eq!((-1.5f64).trunc(), -1.0f64);
+        assert_approx_eq!((-1.7f64).trunc(), -1.0f64);
     }
 
     #[test]
     fn test_fract() {
-        assert_fuzzy_eq!(1.0f64.fract(), 0.0f64);
-        assert_fuzzy_eq!(1.3f64.fract(), 0.3f64);
-        assert_fuzzy_eq!(1.5f64.fract(), 0.5f64);
-        assert_fuzzy_eq!(1.7f64.fract(), 0.7f64);
-        assert_fuzzy_eq!(0.0f64.fract(), 0.0f64);
-        assert_fuzzy_eq!((-0.0f64).fract(), -0.0f64);
-        assert_fuzzy_eq!((-1.0f64).fract(), -0.0f64);
-        assert_fuzzy_eq!((-1.3f64).fract(), -0.3f64);
-        assert_fuzzy_eq!((-1.5f64).fract(), -0.5f64);
-        assert_fuzzy_eq!((-1.7f64).fract(), -0.7f64);
+        assert_approx_eq!(1.0f64.fract(), 0.0f64);
+        assert_approx_eq!(1.3f64.fract(), 0.3f64);
+        assert_approx_eq!(1.5f64.fract(), 0.5f64);
+        assert_approx_eq!(1.7f64.fract(), 0.7f64);
+        assert_approx_eq!(0.0f64.fract(), 0.0f64);
+        assert_approx_eq!((-0.0f64).fract(), -0.0f64);
+        assert_approx_eq!((-1.0f64).fract(), -0.0f64);
+        assert_approx_eq!((-1.3f64).fract(), -0.3f64);
+        assert_approx_eq!((-1.5f64).fract(), -0.5f64);
+        assert_approx_eq!((-1.7f64).fract(), -0.7f64);
     }
 
     #[test]
     fn test_real_consts() {
-        assert_fuzzy_eq!(Real::two_pi::<f64>(), 2.0 * Real::pi::<f64>());
-        assert_fuzzy_eq!(Real::frac_pi_2::<f64>(), Real::pi::<f64>() / 2f64);
-        assert_fuzzy_eq!(Real::frac_pi_3::<f64>(), Real::pi::<f64>() / 3f64);
-        assert_fuzzy_eq!(Real::frac_pi_4::<f64>(), Real::pi::<f64>() / 4f64);
-        assert_fuzzy_eq!(Real::frac_pi_6::<f64>(), Real::pi::<f64>() / 6f64);
-        assert_fuzzy_eq!(Real::frac_pi_8::<f64>(), Real::pi::<f64>() / 8f64);
-        assert_fuzzy_eq!(Real::frac_1_pi::<f64>(), 1f64 / Real::pi::<f64>());
-        assert_fuzzy_eq!(Real::frac_2_pi::<f64>(), 2f64 / Real::pi::<f64>());
-        assert_fuzzy_eq!(Real::frac_2_sqrtpi::<f64>(), 2f64 / Real::pi::<f64>().sqrt());
-        assert_fuzzy_eq!(Real::sqrt2::<f64>(), 2f64.sqrt());
-        assert_fuzzy_eq!(Real::frac_1_sqrt2::<f64>(), 1f64 / 2f64.sqrt());
-        assert_fuzzy_eq!(Real::log2_e::<f64>(), Real::e::<f64>().log2());
-        assert_fuzzy_eq!(Real::log10_e::<f64>(), Real::e::<f64>().log10());
-        assert_fuzzy_eq!(Real::log_2::<f64>(), 2f64.log());
-        assert_fuzzy_eq!(Real::log_10::<f64>(), 10f64.log());
+        assert_approx_eq!(Real::two_pi::<f64>(), 2.0 * Real::pi::<f64>());
+        assert_approx_eq!(Real::frac_pi_2::<f64>(), Real::pi::<f64>() / 2f64);
+        assert_approx_eq!(Real::frac_pi_3::<f64>(), Real::pi::<f64>() / 3f64);
+        assert_approx_eq!(Real::frac_pi_4::<f64>(), Real::pi::<f64>() / 4f64);
+        assert_approx_eq!(Real::frac_pi_6::<f64>(), Real::pi::<f64>() / 6f64);
+        assert_approx_eq!(Real::frac_pi_8::<f64>(), Real::pi::<f64>() / 8f64);
+        assert_approx_eq!(Real::frac_1_pi::<f64>(), 1f64 / Real::pi::<f64>());
+        assert_approx_eq!(Real::frac_2_pi::<f64>(), 2f64 / Real::pi::<f64>());
+        assert_approx_eq!(Real::frac_2_sqrtpi::<f64>(), 2f64 / Real::pi::<f64>().sqrt());
+        assert_approx_eq!(Real::sqrt2::<f64>(), 2f64.sqrt());
+        assert_approx_eq!(Real::frac_1_sqrt2::<f64>(), 1f64 / 2f64.sqrt());
+        assert_approx_eq!(Real::log2_e::<f64>(), Real::e::<f64>().log2());
+        assert_approx_eq!(Real::log10_e::<f64>(), Real::e::<f64>().log10());
+        assert_approx_eq!(Real::log_2::<f64>(), 2f64.log());
+        assert_approx_eq!(Real::log_10::<f64>(), 10f64.log());
     }
 
     #[test]
diff --git a/src/libcore/num/float.rs b/src/libcore/num/float.rs
index 61dd741b671b5..a548165326396 100644
--- a/src/libcore/num/float.rs
+++ b/src/libcore/num/float.rs
@@ -837,15 +837,6 @@ mod tests {
     use super::*;
     use prelude::*;
 
-    macro_rules! assert_fuzzy_eq(
-        ($a:expr, $b:expr) => ({
-            let a = $a, b = $b;
-            if !((a - b).abs() < 1.0e-6) {
-                fail!(fmt!("The values were not approximately equal. Found: %? and %?", a, b));
-            }
-        })
-    )
-
     #[test]
     fn test_num() {
         num::test_num(10f, 2f);
@@ -875,91 +866,91 @@ mod tests {
 
     #[test]
     fn test_floor() {
-        assert_fuzzy_eq!(1.0f.floor(), 1.0f);
-        assert_fuzzy_eq!(1.3f.floor(), 1.0f);
-        assert_fuzzy_eq!(1.5f.floor(), 1.0f);
-        assert_fuzzy_eq!(1.7f.floor(), 1.0f);
-        assert_fuzzy_eq!(0.0f.floor(), 0.0f);
-        assert_fuzzy_eq!((-0.0f).floor(), -0.0f);
-        assert_fuzzy_eq!((-1.0f).floor(), -1.0f);
-        assert_fuzzy_eq!((-1.3f).floor(), -2.0f);
-        assert_fuzzy_eq!((-1.5f).floor(), -2.0f);
-        assert_fuzzy_eq!((-1.7f).floor(), -2.0f);
+        assert_approx_eq!(1.0f.floor(), 1.0f);
+        assert_approx_eq!(1.3f.floor(), 1.0f);
+        assert_approx_eq!(1.5f.floor(), 1.0f);
+        assert_approx_eq!(1.7f.floor(), 1.0f);
+        assert_approx_eq!(0.0f.floor(), 0.0f);
+        assert_approx_eq!((-0.0f).floor(), -0.0f);
+        assert_approx_eq!((-1.0f).floor(), -1.0f);
+        assert_approx_eq!((-1.3f).floor(), -2.0f);
+        assert_approx_eq!((-1.5f).floor(), -2.0f);
+        assert_approx_eq!((-1.7f).floor(), -2.0f);
     }
 
     #[test]
     fn test_ceil() {
-        assert_fuzzy_eq!(1.0f.ceil(), 1.0f);
-        assert_fuzzy_eq!(1.3f.ceil(), 2.0f);
-        assert_fuzzy_eq!(1.5f.ceil(), 2.0f);
-        assert_fuzzy_eq!(1.7f.ceil(), 2.0f);
-        assert_fuzzy_eq!(0.0f.ceil(), 0.0f);
-        assert_fuzzy_eq!((-0.0f).ceil(), -0.0f);
-        assert_fuzzy_eq!((-1.0f).ceil(), -1.0f);
-        assert_fuzzy_eq!((-1.3f).ceil(), -1.0f);
-        assert_fuzzy_eq!((-1.5f).ceil(), -1.0f);
-        assert_fuzzy_eq!((-1.7f).ceil(), -1.0f);
+        assert_approx_eq!(1.0f.ceil(), 1.0f);
+        assert_approx_eq!(1.3f.ceil(), 2.0f);
+        assert_approx_eq!(1.5f.ceil(), 2.0f);
+        assert_approx_eq!(1.7f.ceil(), 2.0f);
+        assert_approx_eq!(0.0f.ceil(), 0.0f);
+        assert_approx_eq!((-0.0f).ceil(), -0.0f);
+        assert_approx_eq!((-1.0f).ceil(), -1.0f);
+        assert_approx_eq!((-1.3f).ceil(), -1.0f);
+        assert_approx_eq!((-1.5f).ceil(), -1.0f);
+        assert_approx_eq!((-1.7f).ceil(), -1.0f);
     }
 
     #[test]
     fn test_round() {
-        assert_fuzzy_eq!(1.0f.round(), 1.0f);
-        assert_fuzzy_eq!(1.3f.round(), 1.0f);
-        assert_fuzzy_eq!(1.5f.round(), 2.0f);
-        assert_fuzzy_eq!(1.7f.round(), 2.0f);
-        assert_fuzzy_eq!(0.0f.round(), 0.0f);
-        assert_fuzzy_eq!((-0.0f).round(), -0.0f);
-        assert_fuzzy_eq!((-1.0f).round(), -1.0f);
-        assert_fuzzy_eq!((-1.3f).round(), -1.0f);
-        assert_fuzzy_eq!((-1.5f).round(), -2.0f);
-        assert_fuzzy_eq!((-1.7f).round(), -2.0f);
+        assert_approx_eq!(1.0f.round(), 1.0f);
+        assert_approx_eq!(1.3f.round(), 1.0f);
+        assert_approx_eq!(1.5f.round(), 2.0f);
+        assert_approx_eq!(1.7f.round(), 2.0f);
+        assert_approx_eq!(0.0f.round(), 0.0f);
+        assert_approx_eq!((-0.0f).round(), -0.0f);
+        assert_approx_eq!((-1.0f).round(), -1.0f);
+        assert_approx_eq!((-1.3f).round(), -1.0f);
+        assert_approx_eq!((-1.5f).round(), -2.0f);
+        assert_approx_eq!((-1.7f).round(), -2.0f);
     }
 
     #[test]
     fn test_trunc() {
-        assert_fuzzy_eq!(1.0f.trunc(), 1.0f);
-        assert_fuzzy_eq!(1.3f.trunc(), 1.0f);
-        assert_fuzzy_eq!(1.5f.trunc(), 1.0f);
-        assert_fuzzy_eq!(1.7f.trunc(), 1.0f);
-        assert_fuzzy_eq!(0.0f.trunc(), 0.0f);
-        assert_fuzzy_eq!((-0.0f).trunc(), -0.0f);
-        assert_fuzzy_eq!((-1.0f).trunc(), -1.0f);
-        assert_fuzzy_eq!((-1.3f).trunc(), -1.0f);
-        assert_fuzzy_eq!((-1.5f).trunc(), -1.0f);
-        assert_fuzzy_eq!((-1.7f).trunc(), -1.0f);
+        assert_approx_eq!(1.0f.trunc(), 1.0f);
+        assert_approx_eq!(1.3f.trunc(), 1.0f);
+        assert_approx_eq!(1.5f.trunc(), 1.0f);
+        assert_approx_eq!(1.7f.trunc(), 1.0f);
+        assert_approx_eq!(0.0f.trunc(), 0.0f);
+        assert_approx_eq!((-0.0f).trunc(), -0.0f);
+        assert_approx_eq!((-1.0f).trunc(), -1.0f);
+        assert_approx_eq!((-1.3f).trunc(), -1.0f);
+        assert_approx_eq!((-1.5f).trunc(), -1.0f);
+        assert_approx_eq!((-1.7f).trunc(), -1.0f);
     }
 
     #[test]
     fn test_fract() {
-        assert_fuzzy_eq!(1.0f.fract(), 0.0f);
-        assert_fuzzy_eq!(1.3f.fract(), 0.3f);
-        assert_fuzzy_eq!(1.5f.fract(), 0.5f);
-        assert_fuzzy_eq!(1.7f.fract(), 0.7f);
-        assert_fuzzy_eq!(0.0f.fract(), 0.0f);
-        assert_fuzzy_eq!((-0.0f).fract(), -0.0f);
-        assert_fuzzy_eq!((-1.0f).fract(), -0.0f);
-        assert_fuzzy_eq!((-1.3f).fract(), -0.3f);
-        assert_fuzzy_eq!((-1.5f).fract(), -0.5f);
-        assert_fuzzy_eq!((-1.7f).fract(), -0.7f);
+        assert_approx_eq!(1.0f.fract(), 0.0f);
+        assert_approx_eq!(1.3f.fract(), 0.3f);
+        assert_approx_eq!(1.5f.fract(), 0.5f);
+        assert_approx_eq!(1.7f.fract(), 0.7f);
+        assert_approx_eq!(0.0f.fract(), 0.0f);
+        assert_approx_eq!((-0.0f).fract(), -0.0f);
+        assert_approx_eq!((-1.0f).fract(), -0.0f);
+        assert_approx_eq!((-1.3f).fract(), -0.3f);
+        assert_approx_eq!((-1.5f).fract(), -0.5f);
+        assert_approx_eq!((-1.7f).fract(), -0.7f);
     }
 
     #[test]
     fn test_real_consts() {
-        assert_fuzzy_eq!(Real::two_pi::<float>(), 2f * Real::pi::<float>());
-        assert_fuzzy_eq!(Real::frac_pi_2::<float>(), Real::pi::<float>() / 2f);
-        assert_fuzzy_eq!(Real::frac_pi_3::<float>(), Real::pi::<float>() / 3f);
-        assert_fuzzy_eq!(Real::frac_pi_4::<float>(), Real::pi::<float>() / 4f);
-        assert_fuzzy_eq!(Real::frac_pi_6::<float>(), Real::pi::<float>() / 6f);
-        assert_fuzzy_eq!(Real::frac_pi_8::<float>(), Real::pi::<float>() / 8f);
-        assert_fuzzy_eq!(Real::frac_1_pi::<float>(), 1f / Real::pi::<float>());
-        assert_fuzzy_eq!(Real::frac_2_pi::<float>(), 2f / Real::pi::<float>());
-        assert_fuzzy_eq!(Real::frac_2_sqrtpi::<float>(), 2f / Real::pi::<float>().sqrt());
-        assert_fuzzy_eq!(Real::sqrt2::<float>(), 2f.sqrt());
-        assert_fuzzy_eq!(Real::frac_1_sqrt2::<float>(), 1f / 2f.sqrt());
-        assert_fuzzy_eq!(Real::log2_e::<float>(), Real::e::<float>().log2());
-        assert_fuzzy_eq!(Real::log10_e::<float>(), Real::e::<float>().log10());
-        assert_fuzzy_eq!(Real::log_2::<float>(), 2f.log());
-        assert_fuzzy_eq!(Real::log_10::<float>(), 10f.log());
+        assert_approx_eq!(Real::two_pi::<float>(), 2f * Real::pi::<float>());
+        assert_approx_eq!(Real::frac_pi_2::<float>(), Real::pi::<float>() / 2f);
+        assert_approx_eq!(Real::frac_pi_3::<float>(), Real::pi::<float>() / 3f);
+        assert_approx_eq!(Real::frac_pi_4::<float>(), Real::pi::<float>() / 4f);
+        assert_approx_eq!(Real::frac_pi_6::<float>(), Real::pi::<float>() / 6f);
+        assert_approx_eq!(Real::frac_pi_8::<float>(), Real::pi::<float>() / 8f);
+        assert_approx_eq!(Real::frac_1_pi::<float>(), 1f / Real::pi::<float>());
+        assert_approx_eq!(Real::frac_2_pi::<float>(), 2f / Real::pi::<float>());
+        assert_approx_eq!(Real::frac_2_sqrtpi::<float>(), 2f / Real::pi::<float>().sqrt());
+        assert_approx_eq!(Real::sqrt2::<float>(), 2f.sqrt());
+        assert_approx_eq!(Real::frac_1_sqrt2::<float>(), 1f / 2f.sqrt());
+        assert_approx_eq!(Real::log2_e::<float>(), Real::e::<float>().log2());
+        assert_approx_eq!(Real::log10_e::<float>(), Real::e::<float>().log10());
+        assert_approx_eq!(Real::log_2::<float>(), 2f.log());
+        assert_approx_eq!(Real::log_10::<float>(), 10f.log());
     }
 
     #[test]
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 02721a02fbd0c..9363807ab9b9e 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -483,6 +483,42 @@ pub fn core_macros() -> ~str {
         )
     )
 
+    macro_rules! assert_approx_eq (
+        ($given:expr , $expected:expr) => (
+            {
+                use core::cmp::ApproxEq;
+
+                let given_val = $given;
+                let expected_val = $expected;
+                // check both directions of equality....
+                if !(
+                    given_val.approx_eq(&expected_val) &&
+                    expected_val.approx_eq(&given_val)
+                ) {
+                    fail!(\"left: %? does not approximately equal right: %?\",
+                          given_val, expected_val);
+                }
+            }
+        );
+        ($given:expr , $expected:expr , $epsilon:expr) => (
+            {
+                use core::cmp::ApproxEq;
+
+                let given_val = $given;
+                let expected_val = $expected;
+                let epsilon_val = $epsilon;
+                // check both directions of equality....
+                if !(
+                    given_val.approx_eq_eps(&expected_val, &epsilon_val) &&
+                    expected_val.approx_eq_eps(&given_val, &epsilon_val)
+                ) {
+                    fail!(\"left: %? does not approximately equal right: %? with epsilon: %?\",
+                          given_val, expected_val, epsilon_val);
+                }
+            }
+        )
+    )
+
     macro_rules! condition (
 
         { $c:ident: $in:ty -> $out:ty; } => {
diff --git a/src/test/run-fail/assert-approx-eq-eps-macro-fail.rs b/src/test/run-fail/assert-approx-eq-eps-macro-fail.rs
new file mode 100644
index 0000000000000..c0c20f7af4351
--- /dev/null
+++ b/src/test/run-fail/assert-approx-eq-eps-macro-fail.rs
@@ -0,0 +1,14 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// error-pattern:left: 1.0000001 does not approximately equal right: 1 with epsilon: 0.0000001
+pub fn main() {
+    assert_approx_eq!(1.0000001f, 1.0f, 1.0e-7);
+}
diff --git a/src/test/run-fail/assert-approx-eq-macro-fail.rs b/src/test/run-fail/assert-approx-eq-macro-fail.rs
new file mode 100644
index 0000000000000..43de4f92b63b1
--- /dev/null
+++ b/src/test/run-fail/assert-approx-eq-macro-fail.rs
@@ -0,0 +1,14 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// error-pattern:left: 1.00001 does not approximately equal right: 1
+pub fn main() {
+    assert_approx_eq!(1.00001f, 1.0f);
+}
diff --git a/src/test/run-pass/assert-approx-eq-macro-success.rs b/src/test/run-pass/assert-approx-eq-macro-success.rs
new file mode 100644
index 0000000000000..5c7c11ef50343
--- /dev/null
+++ b/src/test/run-pass/assert-approx-eq-macro-success.rs
@@ -0,0 +1,16 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub fn main() {
+    assert_approx_eq!(1.0f, 1.0f);
+    assert_approx_eq!(1.0000001f, 1.0f);
+    assert_approx_eq!(1.0000001f, 1.0f, 1.0e-6);
+    assert_approx_eq!(1.000001f, 1.0f, 1.0e-5);
+}