Basic knowledge of self and regions

src/cell.rs

@@ -0,0 +1,97 @@
+use std::collections::HashSet;
+
+#[derive(Clone, Debug, Copy, Hash, Eq, PartialEq)]
+pub enum CellValue {
+    One,
+    Two,
+    Three,
+    Four,
+    Five,
+    Six,
+    Seven,
+    Eight,
+    Nine,
+}
+
+pub struct Cell {
+    value: Option<CellValue>,
+    candidates: HashSet<CellValue>,
+}
+
+impl Cell {
+    pub fn value(&self) -> Option<CellValue> {
+        self.value
+    }
+
+    pub fn set_value(&mut self, value: CellValue) {
+        self.value = Some(value);
+    }
+
+    pub fn candidates(&self) -> HashSet<CellValue> {
+        self.candidates.clone()
+    }
+
+    pub fn remove_candidate(&mut self, value: CellValue) {
+        self.candidates.remove(&value);
+    }
+}
+
+impl Default for Cell {
+    fn default() -> Cell {
+        let mut candidates = HashSet::new();
+        candidates.insert(CellValue::One);
+        candidates.insert(CellValue::Two);
+        candidates.insert(CellValue::Three);
+        candidates.insert(CellValue::Four);
+        candidates.insert(CellValue::Five);
+        candidates.insert(CellValue::Six);
+        candidates.insert(CellValue::Seven);
+        candidates.insert(CellValue::Eight);
+        candidates.insert(CellValue::Nine);
+        Cell {
+            value: None,
+            candidates,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use assertables::{assert_contains, assert_not_contains};
+
+    #[test]
+    fn inits_empty() {
+        let cell = Cell::default();
+        assert!(cell.value().is_none());
+    }
+
+    #[test]
+    fn has_all_candidates() {
+        let cell = Cell::default();
+        assert_contains!(cell.candidates(), &CellValue::One);
+        assert_contains!(cell.candidates(), &CellValue::Two);
+        assert_contains!(cell.candidates(), &CellValue::Three);
+        assert_contains!(cell.candidates(), &CellValue::Four);
+        assert_contains!(cell.candidates(), &CellValue::Five);
+        assert_contains!(cell.candidates(), &CellValue::Six);
+        assert_contains!(cell.candidates(), &CellValue::Seven);
+        assert_contains!(cell.candidates(), &CellValue::Eight);
+        assert_contains!(cell.candidates(), &CellValue::Nine);
+    }
+
+    #[test]
+    fn removed_candidate_is_gone() {
+        let mut cell = Cell::default();
+        cell.remove_candidate(CellValue::One);
+        assert_not_contains!(cell.candidates(), &CellValue::One);
+        assert_contains!(cell.candidates(), &CellValue::Two);
+        assert_contains!(cell.candidates(), &CellValue::Three);
+        assert_contains!(cell.candidates(), &CellValue::Four);
+        assert_contains!(cell.candidates(), &CellValue::Five);
+        assert_contains!(cell.candidates(), &CellValue::Six);
+        assert_contains!(cell.candidates(), &CellValue::Seven);
+        assert_contains!(cell.candidates(), &CellValue::Eight);
+        assert_contains!(cell.candidates(), &CellValue::Nine);
+    }
+}