Remove Duplicates: compare the text cells show

Excel decides duplicates by what a cell displays, not the value stored:
the same date shown as 3/8/2006 and as Mar 8, 2006 is two values, while
1.01 and 1.02 both shown as 1.0 are duplicates. Remove Duplicates
compared stored values, so it did the opposite in both cases.

crates/engine/src/cmd/data.rs

@@ -691,8 +691,11 @@ fn remove_duplicates(s: &mut Session, p: &Json) -> Result<Json> {
         let Some(sh) = cx.wb.sheet(sheet) else { return Ok(()) };
         let mut seen = std::collections::HashSet::new();
         let mut keep: Vec<u32> = Vec::new();
+        // Cells are compared by the text they show, as in Excel: the same date in two formats
+        // isn't a duplicate, while 1.01 and 1.02 shown as 1.0 are.
+        let shown = |c: CellRef| crate::display::format(&sh.value(c), cx.wb.styles.get(sh.style_id(c)).num_fmt.as_str(), &cx.wb).text;
         for row in start..=r.end.row {
-            let key: Vec<String> = cols.iter().map(|c| sh.value(CellRef::new(row, *c)).display().to_lowercase()).collect();
+            let key: Vec<String> = cols.iter().map(|c| shown(CellRef::new(row, *c)).to_lowercase()).collect();
             if seen.insert(key) {
                 keep.push(row);
             } else {

crates/engine/src/tests.rs

@@ -615,6 +615,18 @@ fn case_sensitive_sort_puts_lowercase_first() {
     assert_eq!(col, ["a", "A", "aB", "Ab", "b", "B"].map(Value::from));
 }
 
+#[test]
+fn remove_duplicates_compares_shown_text() {
+    let mut s = s();
+    s.execute("range.setValues", json!({"range": "A1", "values": [["Date", "Price"], ["2006-03-08", 1.01], ["2006-03-08", 1.02]]})).unwrap();
+    s.execute("home.numberFormat", json!({"range": "A3", "code": "mmm d, yyyy"})).unwrap();
+    s.execute("home.numberFormat", json!({"range": "B2:B3", "code": "0.0"})).unwrap();
+    let r = s.execute("data.removeDuplicates", json!({"range": "A1:A3", "header": true})).unwrap();
+    assert_eq!(r["removed"], 0);
+    let r = s.execute("data.removeDuplicates", json!({"range": "B1:B3", "header": true})).unwrap();
+    assert_eq!(r["removed"], 1);
+}
+
 #[test]
 fn formatting_and_styles() {
     let mut s = s();