diff --git a/src/lib.rs b/src/lib.rs
index 739c26a..187255a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -143,9 +143,8 @@ impl Dictionary for HashMap<String, f64> {
     }
 
     fn is_word_valid(&self, word: &Word) -> bool {
-
-
-        todo!()
+        let text = word.to_string();
+        self.contains_key(&text)
     }
 }
 
@@ -813,6 +812,7 @@ mod tests {
         board.get_cell_mut(Coordinates(6, 0)).unwrap().value = Some(Letter::new_fixed('L', 1));
 
         fn check_board(board: &mut Board, inverted: bool) {
+            let dictionary = HashMap::create("resources/dictionary.csv");
             println!("{}", board);
             let words = board.find_played_words();
             match words {
@@ -820,6 +820,7 @@ mod tests {
                     assert_eq!(x.len(), 1);
                     let word = x.get(0).unwrap();
                     assert_eq!(word.to_string(), "JOEL");
+                    assert!(!dictionary.is_word_valid(word));
 
                     assert_eq!(word.calculate_score(), 8 + 1 + 2 + 1);
                 }
@@ -852,6 +853,7 @@ mod tests {
 
                     assert_eq!(x.to_string(), "EGG");
                     assert_eq!(x.calculate_score(), 2 + 2 + 2);
+                    assert!(dictionary.is_word_valid(&x));
 
                 }
             }
@@ -863,10 +865,12 @@ mod tests {
                     let word = x.get(0).unwrap();
                     assert_eq!(word.to_string(), "EGG");
                     assert_eq!(word.calculate_score(), 2 + 2 + 2);
+                    assert!(dictionary.is_word_valid(word));
 
                     let word = x.get(1).unwrap();
                     assert_eq!(word.to_string(), "JOEL");
                     assert_eq!(word.calculate_score(), 8 + 1 + 2 + 1);
+                    assert!(!dictionary.is_word_valid(word));
                 }
                 Err(e) => { panic!("Expected to find a word to play; found error {}", e) }
             }