Move buffer rows test into WrapMap randomized test

Also, change the way we assert on buffer rows to reflect the fact
that we will still show the line as soft-wrapped when there is a
fold that spans multiple buffer rows.

zed/src/editor/display_map.rs

@@ -290,75 +290,10 @@ mod tests {
         language::{Language, LanguageConfig},
         settings::Theme,
         test::*,
-        util::RandomCharIter,
     };
     use buffer::History;
     use gpui::MutableAppContext;
-    use rand::prelude::*;
-    use std::{env, sync::Arc};
-
-    #[gpui::test]
-    async fn test_random(mut cx: gpui::TestAppContext) {
-        cx.foreground().set_block_on_ticks(usize::MAX..=usize::MAX);
-        let iterations = env::var("ITERATIONS")
-            .map(|i| i.parse().expect("invalid `ITERATIONS` variable"))
-            .unwrap_or(100);
-        let operations = env::var("OPERATIONS")
-            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
-            .unwrap_or(10);
-        let seed_range = if let Ok(seed) = env::var("SEED") {
-            let seed = seed.parse().expect("invalid `SEED` variable");
-            seed..seed + 1
-        } else {
-            0..iterations
-        };
-        let font_cache = cx.font_cache();
-
-        for seed in seed_range {
-            dbg!(seed);
-            let mut rng = StdRng::seed_from_u64(seed);
-            let settings = Settings {
-                buffer_font_family: font_cache.load_family(&["Helvetica"]).unwrap(),
-                ui_font_family: font_cache.load_family(&["Helvetica"]).unwrap(),
-                buffer_font_size: 12.0,
-                ui_font_size: 12.0,
-                tab_size: rng.gen_range(1..=4),
-                theme: Arc::new(Theme::default()),
-            };
-
-            let buffer = cx.add_model(|cx| {
-                let len = rng.gen_range(0..10);
-                let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
-                log::info!("Initial buffer text: {:?}", text);
-                Buffer::new(0, text, cx)
-            });
-            let wrap_width = Some(rng.gen_range(20.0..=100.0));
-            let map = cx.add_model(|cx| DisplayMap::new(buffer.clone(), settings, wrap_width, cx));
-
-            for _op_ix in 0..operations {
-                buffer.update(&mut cx, |buffer, cx| buffer.randomly_mutate(&mut rng, cx));
-                let snapshot = map.update(&mut cx, |map, cx| map.snapshot(cx));
-                let expected_buffer_rows = (0..=snapshot.max_point().row())
-                    .map(|display_row| {
-                        DisplayPoint::new(display_row, 0)
-                            .to_buffer_point(&snapshot, Bias::Left)
-                            .row
-                    })
-                    .collect::<Vec<_>>();
-                for start_display_row in 0..expected_buffer_rows.len() {
-                    assert_eq!(
-                        snapshot
-                            .buffer_rows(start_display_row as u32)
-                            .map(|(row, _)| row)
-                            .collect::<Vec<_>>(),
-                        &expected_buffer_rows[start_display_row..],
-                        "invalid buffer_rows({}..)",
-                        start_display_row
-                    );
-                }
-            }
-        }
-    }
+    use std::sync::Arc;
 
     #[gpui::test]
     async fn test_soft_wraps(mut cx: gpui::TestAppContext) {

zed/src/editor/display_map/tab_map.rs

@@ -91,8 +91,8 @@ impl TabMap {
 
 #[derive(Clone)]
 pub struct Snapshot {
-    fold_snapshot: FoldSnapshot,
-    tab_size: usize,
+    pub fold_snapshot: FoldSnapshot,
+    pub tab_size: usize,
 }
 
 impl Snapshot {

zed/src/editor/display_map/wrap_map.rs

@@ -583,6 +583,31 @@ impl Snapshot {
                     }
                 }
             }
+
+            let mut expected_buffer_rows = Vec::new();
+            let mut buffer_row = 0;
+            let mut prev_tab_row = 0;
+            for display_row in 0..=self.max_point().row() {
+                let tab_point = self.to_tab_point(WrapPoint::new(display_row, 0));
+                if tab_point.row() != prev_tab_row {
+                    let fold_point = self.tab_snapshot.to_fold_point(tab_point, Bias::Left).0;
+                    let buffer_point = fold_point.to_buffer_point(&self.tab_snapshot.fold_snapshot);
+                    buffer_row = buffer_point.row;
+                    prev_tab_row = tab_point.row();
+                }
+                expected_buffer_rows.push(buffer_row);
+            }
+
+            for start_display_row in 0..expected_buffer_rows.len() {
+                assert_eq!(
+                    self.buffer_rows(start_display_row as u32)
+                        .map(|(row, _)| row)
+                        .collect::<Vec<_>>(),
+                    &expected_buffer_rows[start_display_row..],
+                    "invalid buffer_rows({}..)",
+                    start_display_row
+                );
+            }
         }
     }
 }