Use similar-asserts for better test output

Cargo.lock

@@ -642,6 +642,17 @@ dependencies = [
  "piper",
 ]
 
+[[package]]
+name = "bstr"
+version = "1.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "531a9155a481e2ee699d4f98f43c0ca4ff8ee1bfd55c31e9e98fb29d2b176fe0"
+dependencies = [
+ "memchr",
+ "regex-automata",
+ "serde",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.16.0"
@@ -896,6 +907,18 @@ dependencies = [
  "env_logger",
 ]
 
+[[package]]
+name = "console"
+version = "0.15.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "054ccb5b10f9f2cbf51eb355ca1d05c2d279ce1804688d0db74b4733a5aeafd8"
+dependencies = [
+ "encode_unicode",
+ "libc",
+ "once_cell",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "core-foundation"
 version = "0.9.4"
@@ -1421,6 +1444,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "encode_unicode"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34aa73646ffb006b8f5147f3dc182bd4bcb190227ce861fc4a4844bf8e3cb2c0"
+
 [[package]]
 name = "endi"
 version = "1.1.0"
@@ -1521,6 +1550,7 @@ dependencies = [
  "profiling",
  "rayon",
  "serde",
+ "similar-asserts",
 ]
 
 [[package]]
@@ -2390,7 +2420,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4979f22fdb869068da03c9f7528f8297c6fd2606bc3a4affe42e6a823fdb8da4"
 dependencies = [
  "cfg-if",
- "windows-targets 0.48.5",
+ "windows-targets 0.52.6",
 ]
 
 [[package]]
@@ -3670,6 +3700,26 @@ version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d66dc143e6b11c1eddc06d5c423cfc97062865baf299914ab64caa38182078fe"
 
+[[package]]
+name = "similar"
+version = "2.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbbb5d9659141646ae647b42fe094daf6c6192d1620870b449d9557f748b2daa"
+dependencies = [
+ "bstr",
+ "unicode-segmentation",
+]
+
+[[package]]
+name = "similar-asserts"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5b441962c817e33508847a22bd82f03a30cff43642dc2fae8b050566121eb9a"
+dependencies = [
+ "console",
+ "similar",
+]
+
 [[package]]
 name = "simplecss"
 version = "0.2.1"

Cargo.toml

@@ -96,6 +96,7 @@ puffin_http = "0.16"
 raw-window-handle = "0.6.0"
 ron = "0.8"
 serde = { version = "1", features = ["derive"] }
+similar-asserts = "1.4.2"
 thiserror = "1.0.37"
 type-map = "0.5.0"
 wasm-bindgen = "0.2"

crates/epaint/Cargo.toml

@@ -101,6 +101,7 @@ backtrace = { workspace = true, optional = true }
 
 [dev-dependencies]
 criterion.workspace = true
+similar-asserts.workspace = true
 
 
 [[bench]]

crates/epaint/src/text/fonts.rs

@@ -980,3 +980,88 @@ impl FontImplCache {
             .clone()
     }
 }
+
+#[cfg(feature = "default_fonts")]
+#[cfg(test)]
+mod tests {
+    use core::f32;
+
+    use super::*;
+    use crate::{text::TextFormat, Stroke};
+    use ecolor::Color32;
+
+    fn jobs() -> Vec<LayoutJob> {
+        // TODO: add more tests here with newlines etc
+        vec![
+            LayoutJob::simple(
+                "Simplest test.".to_owned(),
+                FontId::new(14.0, FontFamily::Monospace),
+                Color32::WHITE,
+                f32::INFINITY,
+            ),
+            LayoutJob::simple(
+                "The is some text that may be long.\nDet kanske också finns lite ÅÄÖ här."
+                    .to_owned(),
+                FontId::new(14.0, FontFamily::Proportional),
+                Color32::WHITE,
+                50.0,
+            ),
+            {
+                let mut job = LayoutJob {
+                    first_row_min_height: 20.0,
+                    justify: true,
+                    ..Default::default()
+                };
+                job.append(
+                    "The first paragraph has some leading space.\n",
+                    16.0,
+                    TextFormat {
+                        font_id: FontId::new(14.0, FontFamily::Proportional),
+                        ..Default::default()
+                    },
+                );
+                job.append(
+                    "The second paragraph has underline and strikthrough, and has some non-ASCII characters: ÅÄÖ.",
+                    0.0,
+                    TextFormat {
+                        font_id: FontId::new(15.0, FontFamily::Monospace),
+                        underline: Stroke::new(1.0, Color32::RED),
+                        strikethrough: Stroke::new(1.0, Color32::GREEN),
+                        ..Default::default()
+                    },
+                );
+                job.append(
+                    "The last paragraph is kind of boring, bust has italics.",
+                    0.0,
+                    TextFormat {
+                        font_id: FontId::new(10.0, FontFamily::Proportional),
+                        italics: true,
+                        ..Default::default()
+                    },
+                );
+
+                job
+            },
+        ]
+    }
+
+    #[test]
+    fn test_split_paragraphs() {
+        for pixels_per_point in [1.0, 2.0_f32.sqrt(), 2.0] {
+            let max_texture_side = 4096;
+            let mut fonts = FontsImpl::new(
+                pixels_per_point,
+                max_texture_side,
+                FontDefinitions::default(),
+            );
+
+            for job in jobs() {
+                let as_whole = GalleyCache::default().layout(&mut fonts, job.clone(), false);
+
+                let split = GalleyCache::default().layout(&mut fonts, job.clone(), true);
+
+                similar_asserts::assert_eq!(split, as_whole, "Input text: '{}'", job.text);
+            }
+        }
+    }
+}