refactor: colocate cmd tests with their modules

Move tests from the monolithic tests.rs into #[cfg(test)] mod tests
blocks in each command module. Shared test helpers live in
mod.rs::test_helpers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Executed-By: fido

src/command/cmd/commit.rs

@@ -5,6 +5,133 @@ use crate::ui::effect::{self, Effect};
 use super::core::{Cmd, CmdContext};
 use super::navigation::{viewport_effects, CursorState, EnterAdvance};
 
+#[cfg(test)]
+mod tests {
+    use std::collections::HashMap;
+
+    use super::*;
+    use crate::command::cmd::test_helpers::*;
+    use crate::model::Model;
+
+    #[test]
+    fn commit_formula_with_categories_adds_formula() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut bufs = HashMap::new();
+        bufs.insert("formula".to_string(), "Profit = Revenue - Cost".to_string());
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.buffers = &bufs;
+        let effects = CommitFormula.execute(&ctx);
+        let dbg = effects_debug(&effects);
+        assert!(
+            dbg.contains("AddFormula"),
+            "Expected AddFormula, got: {dbg}"
+        );
+        assert!(
+            dbg.contains("FormulaPanel"),
+            "Expected return to FormulaPanel, got: {dbg}"
+        );
+    }
+
+    #[test]
+    fn commit_formula_without_regular_categories_shows_status() {
+        let m = Model::new("Empty");
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut bufs = HashMap::new();
+        bufs.insert("formula".to_string(), "X = Y + Z".to_string());
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.buffers = &bufs;
+        let effects = CommitFormula.execute(&ctx);
+        let dbg = effects_debug(&effects);
+        assert!(
+            !dbg.contains("AddFormula"),
+            "Should not add formula when only virtual categories exist, got: {dbg}"
+        );
+        assert!(
+            dbg.contains("Add at least one category first"),
+            "Expected status message, got: {dbg}"
+        );
+    }
+
+    #[test]
+    fn commit_category_add_with_name_produces_add_effect() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut bufs = HashMap::new();
+        bufs.insert("category".to_string(), "Region".to_string());
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.buffers = &bufs;
+        let effects = CommitCategoryAdd.execute(&ctx);
+        let dbg = effects_debug(&effects);
+        assert!(
+            dbg.contains("AddCategory"),
+            "Expected AddCategory, got: {dbg}"
+        );
+    }
+
+    #[test]
+    fn commit_category_add_with_empty_buffer_returns_to_panel() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut bufs = HashMap::new();
+        bufs.insert("category".to_string(), "".to_string());
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.buffers = &bufs;
+        let effects = CommitCategoryAdd.execute(&ctx);
+        let dbg = effects_debug(&effects);
+        assert!(
+            dbg.contains("CategoryPanel"),
+            "Expected return to CategoryPanel, got: {dbg}"
+        );
+    }
+
+    #[test]
+    fn commit_item_add_with_name_produces_add_item() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut bufs = HashMap::new();
+        bufs.insert("item".to_string(), "March".to_string());
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        let item_add_mode = AppMode::item_add("Month".to_string());
+        ctx.mode = &item_add_mode;
+        ctx.buffers = &bufs;
+        let effects = CommitItemAdd.execute(&ctx);
+        let dbg = effects_debug(&effects);
+        assert!(dbg.contains("AddItem"), "Expected AddItem, got: {dbg}");
+    }
+
+    #[test]
+    fn commit_item_add_outside_item_add_mode_returns_empty() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let ctx = make_ctx(&m, &layout, &reg);
+        let effects = CommitItemAdd.execute(&ctx);
+        assert!(effects.is_empty());
+    }
+
+    #[test]
+    fn commit_export_produces_export_and_normal_mode() {
+        let m = two_cat_model();
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut bufs = HashMap::new();
+        bufs.insert("export".to_string(), "/tmp/test.csv".to_string());
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        ctx.buffers = &bufs;
+        let effects = CommitExport.execute(&ctx);
+        assert_eq!(effects.len(), 2);
+        let dbg = effects_debug(&effects);
+        assert!(dbg.contains("ExportCsv"), "Expected ExportCsv, got: {dbg}");
+        assert!(dbg.contains("Normal"), "Expected Normal mode, got: {dbg}");
+    }
+}
+
 // ── Commit commands (mode-specific buffer consumers) ────────────────────────
 
 /// Commit a cell value: for synthetic records keys, stage in drill pending edits