chore: start testing the grid

src/ui/grid.rs

@@ -37,35 +37,15 @@ impl<'a> GridWidget<'a> {
         let col_cats: Vec<&str> = view.categories_on(Axis::Column);
         let page_cats: Vec<&str> = view.categories_on(Axis::Page);
 
-        // Gather row items
-        let row_items: Vec<Vec<String>> = if row_cats.is_empty() {
-            vec![vec![]]
-        } else {
-            let cat_name = row_cats[0];
-            let cat = match self.model.category(cat_name) {
-                Some(c) => c,
-                None => return,
-            };
-            cat.ordered_item_names().into_iter()
-                .filter(|item| !view.is_hidden(cat_name, item))
-                .map(|item| vec![item.to_string()])
-                .collect()
-        };
+        // Gather row items — cross-product of all row-axis categories
+        let row_items: Vec<Vec<String>> = cross_product_items(
+            &row_cats, self.model, view,
+        );
 
-        // Gather col items
-        let col_items: Vec<Vec<String>> = if col_cats.is_empty() {
-            vec![vec![]]
-        } else {
-            let cat_name = col_cats[0];
-            let cat = match self.model.category(cat_name) {
-                Some(c) => c,
-                None => return,
-            };
-            cat.ordered_item_names().into_iter()
-                .filter(|item| !view.is_hidden(cat_name, item))
-                .map(|item| vec![item.to_string()])
-                .collect()
-        };
+        // Gather col items — cross-product of all col-axis categories
+        let col_items: Vec<Vec<String>> = cross_product_items(
+            &col_cats, self.model, view,
+        );
 
         // Page filter coords
         let page_coords: Vec<(String, String)> = page_cats.iter().map(|cat_name| {
@@ -227,6 +207,38 @@ impl<'a> GridWidget<'a> {
     }
 }
 
+/// Returns the cross-product of items across `cats`, filtered by hidden state.
+/// Each element is a Vec of item names, one per category in `cats` order.
+fn cross_product_items(cats: &[&str], model: &Model, view: &crate::view::View) -> Vec<Vec<String>> {
+    if cats.is_empty() {
+        return vec![vec![]];
+    }
+    let mut result: Vec<Vec<String>> = vec![vec![]];
+    for &cat_name in cats {
+        let items: Vec<String> = model
+            .category(cat_name)
+            .map(|c| {
+                c.ordered_item_names()
+                    .into_iter()
+                    .filter(|item| !view.is_hidden(cat_name, item))
+                    .map(String::from)
+                    .collect()
+            })
+            .unwrap_or_default();
+        result = result
+            .into_iter()
+            .flat_map(|prefix| {
+                items.iter().map(move |item| {
+                    let mut row = prefix.clone();
+                    row.push(item.clone());
+                    row
+                })
+            })
+            .collect();
+    }
+    result
+}
+
 impl<'a> Widget for GridWidget<'a> {
     fn render(self, area: Rect, buf: &mut Buffer) {
         let view_name = self.model.active_view
@@ -319,3 +331,245 @@ fn truncate(s: &str, max_width: usize) -> String {
         s.chars().take(max_width).collect()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use ratatui::{buffer::Buffer, layout::Rect, widgets::Widget};
+
+    use crate::model::Model;
+    use crate::model::cell::{CellKey, CellValue};
+    use crate::formula::parse_formula;
+    use crate::ui::app::AppMode;
+    use super::GridWidget;
+
+    // ── Helpers ───────────────────────────────────────────────────────────────
+
+    /// Render a GridWidget into a fresh buffer of the given size.
+    fn render(model: &Model, width: u16, height: u16) -> Buffer {
+        let area = Rect::new(0, 0, width, height);
+        let mut buf = Buffer::empty(area);
+        GridWidget::new(model, &AppMode::Normal, "").render(area, &mut buf);
+        buf
+    }
+
+    /// Flatten the buffer to a multiline string, trailing spaces trimmed per row.
+    fn buf_text(buf: &Buffer) -> String {
+        let w = buf.area().width as usize;
+        buf.content()
+            .chunks(w)
+            .map(|row| row.iter().map(|c| c.symbol()).collect::<String>().trim_end().to_string())
+            .collect::<Vec<_>>()
+            .join("\n")
+    }
+
+    fn coord(pairs: &[(&str, &str)]) -> CellKey {
+        CellKey::new(pairs.iter().map(|(c, i)| (c.to_string(), i.to_string())).collect())
+    }
+
+    /// Minimal model: Type on Row, Month on Column.
+    fn two_cat_model() -> Model {
+        let mut m = Model::new("Test");
+        m.add_category("Type").unwrap();   // → Row
+        m.add_category("Month").unwrap();  // → Column
+        if let Some(c) = m.category_mut("Type") {
+            c.add_item("Food");
+            c.add_item("Clothing");
+        }
+        if let Some(c) = m.category_mut("Month") {
+            c.add_item("Jan");
+            c.add_item("Feb");
+        }
+        m
+    }
+
+    // ── Column headers ────────────────────────────────────────────────────────
+
+    #[test]
+    fn column_headers_appear() {
+        let m = two_cat_model();
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("Jan"),  "expected 'Jan' in:\n{text}");
+        assert!(text.contains("Feb"),  "expected 'Feb' in:\n{text}");
+    }
+
+    // ── Row headers ───────────────────────────────────────────────────────────
+
+    #[test]
+    fn row_headers_appear() {
+        let m = two_cat_model();
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("Food"),     "expected 'Food' in:\n{text}");
+        assert!(text.contains("Clothing"), "expected 'Clothing' in:\n{text}");
+    }
+
+    // ── Cell values ───────────────────────────────────────────────────────────
+
+    #[test]
+    fn cell_value_appears_in_correct_position() {
+        let mut m = two_cat_model();
+        m.set_cell(coord(&[("Type", "Food"), ("Month", "Jan")]), CellValue::Number(123.0));
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("123"), "expected '123' in:\n{text}");
+    }
+
+    #[test]
+    fn multiple_cell_values_all_appear() {
+        let mut m = two_cat_model();
+        m.set_cell(coord(&[("Type", "Food"),     ("Month", "Jan")]), CellValue::Number(100.0));
+        m.set_cell(coord(&[("Type", "Food"),     ("Month", "Feb")]), CellValue::Number(200.0));
+        m.set_cell(coord(&[("Type", "Clothing"), ("Month", "Jan")]), CellValue::Number(50.0));
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("100"), "expected '100' in:\n{text}");
+        assert!(text.contains("200"), "expected '200' in:\n{text}");
+        assert!(text.contains("50"),  "expected '50' in:\n{text}");
+    }
+
+    #[test]
+    fn unset_cells_show_no_value() {
+        let m = two_cat_model();
+        let text = buf_text(&render(&m, 80, 24));
+        // No digits should appear in the data area if nothing is set
+        // (Total row shows "0" — exclude that from this check by looking for non-zero)
+        assert!(!text.contains("100"), "unexpected '100' in:\n{text}");
+    }
+
+    // ── Total row ─────────────────────────────────────────────────────────────
+
+    #[test]
+    fn total_row_label_appears() {
+        let m = two_cat_model();
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("Total"), "expected 'Total' in:\n{text}");
+    }
+
+    #[test]
+    fn total_row_sums_column_correctly() {
+        let mut m = two_cat_model();
+        m.set_cell(coord(&[("Type", "Food"),     ("Month", "Jan")]), CellValue::Number(100.0));
+        m.set_cell(coord(&[("Type", "Clothing"), ("Month", "Jan")]), CellValue::Number(50.0));
+        let text = buf_text(&render(&m, 80, 24));
+        // Food(100) + Clothing(50) = 150 for Jan
+        assert!(text.contains("150"), "expected '150' (total for Jan) in:\n{text}");
+    }
+
+    // ── Page filter bar ───────────────────────────────────────────────────────
+
+    #[test]
+    fn page_filter_bar_shows_category_and_selection() {
+        let mut m = Model::new("Test");
+        m.add_category("Type").unwrap();    // → Row
+        m.add_category("Month").unwrap();   // → Column
+        m.add_category("Payer").unwrap();   // → Page
+        if let Some(c) = m.category_mut("Type")  { c.add_item("Food"); }
+        if let Some(c) = m.category_mut("Month") { c.add_item("Jan"); }
+        if let Some(c) = m.category_mut("Payer") {
+            c.add_item("Alice");
+            c.add_item("Bob");
+        }
+        if let Some(v) = m.active_view_mut() {
+            v.set_page_selection("Payer", "Bob");
+        }
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("Payer = Bob"), "expected 'Payer = Bob' in:\n{text}");
+    }
+
+    #[test]
+    fn page_filter_defaults_to_first_item() {
+        let mut m = Model::new("Test");
+        m.add_category("Type").unwrap();
+        m.add_category("Month").unwrap();
+        m.add_category("Payer").unwrap();
+        if let Some(c) = m.category_mut("Type")  { c.add_item("Food"); }
+        if let Some(c) = m.category_mut("Month") { c.add_item("Jan"); }
+        if let Some(c) = m.category_mut("Payer") {
+            c.add_item("Alice");
+            c.add_item("Bob");
+        }
+        // No explicit selection — should default to first item
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("Payer = Alice"), "expected 'Payer = Alice' in:\n{text}");
+    }
+
+    // ── Formula evaluation ────────────────────────────────────────────────────
+
+    #[test]
+    fn formula_cell_renders_computed_value() {
+        let mut m = Model::new("Test");
+        m.add_category("Measure").unwrap();  // → Row
+        m.add_category("Region").unwrap();   // → Column
+        if let Some(c) = m.category_mut("Measure") {
+            c.add_item("Revenue");
+            c.add_item("Cost");
+            c.add_item("Profit");
+        }
+        if let Some(c) = m.category_mut("Region") { c.add_item("East"); }
+        m.set_cell(coord(&[("Measure", "Revenue"), ("Region", "East")]), CellValue::Number(1000.0));
+        m.set_cell(coord(&[("Measure", "Cost"),    ("Region", "East")]), CellValue::Number(600.0));
+        m.add_formula(parse_formula("Profit = Revenue - Cost", "Measure").unwrap());
+
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("400"), "expected '400' (Profit) in:\n{text}");
+    }
+
+    // ── Multiple categories on same axis (cross-product) ─────────────────────
+
+    #[test]
+    fn two_row_categories_produce_cross_product_labels() {
+        let mut m = Model::new("Test");
+        m.add_category("Type").unwrap();      // → Row
+        m.add_category("Month").unwrap();     // → Column
+        m.add_category("Recipient").unwrap(); // → Page by default; move to Row
+        if let Some(c) = m.category_mut("Type")      { c.add_item("Food"); c.add_item("Clothing"); }
+        if let Some(c) = m.category_mut("Month")     { c.add_item("Jan"); }
+        if let Some(c) = m.category_mut("Recipient") { c.add_item("Alice"); c.add_item("Bob"); }
+        if let Some(v) = m.active_view_mut() {
+            v.set_axis("Recipient", crate::view::Axis::Row);
+        }
+
+        let text = buf_text(&render(&m, 80, 24));
+        // Cross-product rows: Food/Alice, Food/Bob, Clothing/Alice, Clothing/Bob
+        assert!(text.contains("Food/Alice"),     "expected 'Food/Alice' in:\n{text}");
+        assert!(text.contains("Food/Bob"),       "expected 'Food/Bob' in:\n{text}");
+        assert!(text.contains("Clothing/Alice"), "expected 'Clothing/Alice' in:\n{text}");
+        assert!(text.contains("Clothing/Bob"),   "expected 'Clothing/Bob' in:\n{text}");
+    }
+
+    #[test]
+    fn two_row_categories_include_all_coords_in_cell_lookup() {
+        let mut m = Model::new("Test");
+        m.add_category("Type").unwrap();
+        m.add_category("Month").unwrap();
+        m.add_category("Recipient").unwrap();
+        if let Some(c) = m.category_mut("Type")      { c.add_item("Food"); }
+        if let Some(c) = m.category_mut("Month")     { c.add_item("Jan"); }
+        if let Some(c) = m.category_mut("Recipient") { c.add_item("Alice"); c.add_item("Bob"); }
+        if let Some(v) = m.active_view_mut() {
+            v.set_axis("Recipient", crate::view::Axis::Row);
+        }
+        // Set data at the full 3-coordinate key
+        m.set_cell(
+            coord(&[("Month", "Jan"), ("Recipient", "Alice"), ("Type", "Food")]),
+            CellValue::Number(77.0),
+        );
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("77"), "expected '77' in:\n{text}");
+    }
+
+    #[test]
+    fn two_column_categories_produce_cross_product_headers() {
+        let mut m = Model::new("Test");
+        m.add_category("Type").unwrap();   // → Row
+        m.add_category("Month").unwrap();  // → Column
+        m.add_category("Year").unwrap();   // → Page by default; move to Column
+        if let Some(c) = m.category_mut("Type")  { c.add_item("Food"); }
+        if let Some(c) = m.category_mut("Month") { c.add_item("Jan"); }
+        if let Some(c) = m.category_mut("Year")  { c.add_item("2024"); c.add_item("2025"); }
+        if let Some(v) = m.active_view_mut() {
+            v.set_axis("Year", crate::view::Axis::Column);
+        }
+
+        let text = buf_text(&render(&m, 80, 24));
+        assert!(text.contains("Jan/2024"), "expected 'Jan/2024' in:\n{text}");
+        assert!(text.contains("Jan/2025"), "expected 'Jan/2025' in:\n{text}");
+    }
+}