assert_almost_eq! (#55)

jxl/src/lib.rs

@@ -13,4 +13,4 @@ pub mod headers;
 pub mod icc;
 pub mod image;
 pub mod render;
-mod util;
+pub mod util;

jxl/src/render/stages/upsample.rs

@@ -87,7 +87,10 @@ impl RenderPipelineStage for Upsample2x {
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::{error::Result, image::Image, render::test::make_and_run_simple_pipeline};
+    use crate::{
+        error::Result, image::Image, render::test::make_and_run_simple_pipeline,
+        util::test::assert_almost_eq,
+    };
     use test_log::test;
 
     #[test]
@@ -112,7 +115,7 @@ mod test {
             make_and_run_simple_pipeline(stage, &[input], image_size, 123)?.1;
         for x in 0..image_size.0 {
             for y in 0..image_size.1 {
-                assert!((output[0].as_rect().row(y)[x] - val).abs() <= 0.0000001);
+                assert_almost_eq!(output[0].as_rect().row(y)[x], val, 0.0000001);
             }
         }
         Ok(())

jxl/src/util.rs

@@ -3,6 +3,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+#[allow(unused)]
+pub mod test;
+
 mod bits;
 #[allow(unused)]
 mod concat_slice;

jxl/src/util/concat_slice.rs

@@ -18,6 +18,7 @@ impl<'first, 'second> ConcatSlice<'first, 'second> {
         }
     }
 
+    #[allow(clippy::len_without_is_empty)]
     pub fn len(&self) -> usize {
         self.slices.0.len() + self.slices.1.len()
     }

jxl/src/util/test.rs

@@ -0,0 +1,84 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+macro_rules! assert_almost_eq {
+    ($left:expr, $right:expr, $max_error:expr $(,)?) => {
+        match (&$left, &$right, &$max_error) {
+            (left_val, right_val, max_error) => {
+                let diff = if *left_val > *right_val {
+                    *left_val - *right_val
+                } else {
+                    *right_val - *left_val
+                };
+                match diff.partial_cmp(max_error) {
+                    Some(std::cmp::Ordering::Greater) | None => panic!(
+                        "assertion failed: `(left ≈ right)`\n  left: `{:?}`,\n right: `{:?}`,\n max_error: `{:?}`",
+                        left_val, right_val, max_error
+                    ),
+                    _ => {}
+                }
+            }
+        }
+    };
+}
+pub(crate) use assert_almost_eq;
+
+#[cfg(test)]
+mod tests {
+    use std::panic;
+
+    #[test]
+    fn test_with_floats() {
+        assert_almost_eq!(1.0000001f64, 1.0000002, 0.000001);
+        assert_almost_eq!(1.0, 1.1, 0.2);
+    }
+
+    #[test]
+    fn test_with_integers() {
+        assert_almost_eq!(100, 101, 2);
+        assert_almost_eq!(777u32, 770, 7);
+        assert_almost_eq!(500i64, 498, 3);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_panic_float() {
+        assert_almost_eq!(1.0, 1.2, 0.1);
+    }
+    #[test]
+    #[should_panic]
+    fn test_panic_integer() {
+        assert_almost_eq!(100, 105, 2);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_nan_comparison() {
+        assert_almost_eq!(f64::NAN, f64::NAN, 0.1);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_nan_tolerance() {
+        assert_almost_eq!(1.0, 1.0, f64::NAN);
+    }
+
+    #[test]
+    fn test_infinity_tolerance() {
+        assert_almost_eq!(1.0, 1.0, f64::INFINITY);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_nan_comparison_with_infinity_tolerance() {
+        assert_almost_eq!(f32::NAN, f32::NAN, f32::INFINITY);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_infinity_comparison_with_infinity_tolerance() {
+        assert_almost_eq!(f32::INFINITY, f32::INFINITY, f32::INFINITY);
+    }
+}