refactor: move embedded tests into dedicated test directory

tests/unit/wrap.rs

@@ -0,0 +1,133 @@
+use super::*;
+
+fn layout(text: &str, width: usize) -> Vec<Segment> {
+    let mut cache = WrapCache::default();
+    cache.prepare((1, 0), width);
+    cache.segments(0, text).to_vec()
+}
+
+#[test]
+fn words_and_long_words_preserve_every_source_cell() {
+    assert_eq!(
+        layout("one two three", 8),
+        vec![Segment { start: 0, end: 8 }, Segment { start: 8, end: 13 },]
+    );
+    let segments = layout("abcdefgh", 3);
+    assert_eq!(
+        segments,
+        vec![
+            Segment { start: 0, end: 3 },
+            Segment { start: 3, end: 6 },
+            Segment { start: 6, end: 8 },
+        ]
+    );
+    assert_eq!(caret_segment(&segments, 3), 1);
+    assert_eq!(caret_segment(&segments, 8), 2);
+}
+
+#[test]
+fn long_words_do_not_wrap_indentation_onto_an_empty_visual_row() {
+    for source in [
+        "    abcdefghijk",
+        "\tabcdefghijk",
+        "head          abcdefghijk",
+    ] {
+        let expanded = source.replace('\t', "    ");
+        let segments = layout(source, 8);
+        assert_eq!(segments.first().unwrap().start, 0);
+        assert_eq!(segments.last().unwrap().end, expanded.len());
+        assert!(segments.windows(2).all(|pair| pair[0].end == pair[1].start));
+        for segment in segments
+            .iter()
+            .filter(|segment| segment.start < segment.end)
+        {
+            assert!(
+                !expanded[segment.start..segment.end].trim().is_empty(),
+                "whitespace-only visual row {segment:?} in {source:?}"
+            );
+        }
+    }
+}
+
+#[test]
+fn tabs_use_source_stops_and_unicode_graphemes_remain_intact() {
+    assert_eq!(
+        layout("ab\t界e\u{301} z", 4),
+        vec![
+            Segment { start: 0, end: 4 },
+            Segment { start: 4, end: 8 },
+            Segment { start: 8, end: 9 },
+        ]
+    );
+    assert_eq!(
+        layout("界界界", 3),
+        vec![
+            Segment { start: 0, end: 2 },
+            Segment { start: 2, end: 4 },
+            Segment { start: 4, end: 6 },
+        ]
+    );
+    assert_eq!(
+        layout("   \t ", 3),
+        vec![Segment { start: 0, end: 3 }, Segment { start: 3, end: 5 },]
+    );
+}
+
+#[test]
+fn narrow_tabs_preserve_all_expanded_cells_at_original_stops() {
+    assert_eq!(
+        layout("\tX", 2),
+        [
+            Segment { start: 0, end: 2 },
+            Segment { start: 2, end: 4 },
+            Segment { start: 4, end: 5 },
+        ]
+    );
+    assert_eq!(
+        layout("a\tX", 2),
+        [
+            Segment { start: 0, end: 1 },
+            Segment { start: 1, end: 3 },
+            Segment { start: 3, end: 5 },
+            Segment { start: 5, end: 5 },
+        ]
+    );
+    for source in ["\t", "a\t", "ab\tX", "\t\tX"] {
+        let segments = layout(source, 1);
+        assert!(
+            segments
+                .iter()
+                .all(|segment| segment.end - segment.start <= 1)
+        );
+        assert!(segments.windows(2).all(|pair| pair[0].end == pair[1].start));
+        let end = source.graphemes(true).fold(0, |column, grapheme| {
+            column
+                + if grapheme == "\t" {
+                    TAB_WIDTH - column % TAB_WIDTH
+                } else {
+                    1
+                }
+        });
+        assert_eq!(segments.last().unwrap(), &Segment { start: end, end });
+    }
+}
+
+#[test]
+fn full_lines_have_an_insertion_cell_and_cache_invalidation_is_lazy() {
+    let mut cache = WrapCache::default();
+    cache.prepare((7, 2), 4);
+    assert_eq!(
+        cache.segments(90, "abcd"),
+        [Segment { start: 0, end: 4 }, Segment { start: 4, end: 4 },]
+    );
+    assert_eq!(caret_segment(cache.segments(90, "abcd"), 4), 1);
+    assert_eq!(cache.rows.len(), 1);
+    cache.prepare((7, 2), 4);
+    assert_eq!(cache.rows.len(), 1);
+    cache.prepare((7, 2), 8);
+    assert!(cache.rows.is_empty());
+    cache.segments(90, "abcd");
+    cache.prepare((7, 3), 8);
+    assert!(cache.rows.is_empty());
+    assert_eq!(layout("", 0), [Segment { start: 0, end: 0 }]);
+}