diff --git a/planner/src/lib.rs b/planner/src/lib.rs
index f44390b..cde50e2 100644
--- a/planner/src/lib.rs
+++ b/planner/src/lib.rs
@@ -1,5 +1,3 @@
-use std::fmt;
-
 mod solver;
 
 #[cfg(test)]
diff --git a/planner/src/solver.rs b/planner/src/solver.rs
index b1f1379..a9456e6 100644
--- a/planner/src/solver.rs
+++ b/planner/src/solver.rs
@@ -2,6 +2,14 @@ use std::fmt;
 use std::clone::Clone;
 use std::collections::HashMap;
 
+type Variables<'a, V> = HashMap<String, Option<&'a V>>;
+
+enum Assignment<'a, V> {
+    Update(String, &'a V),
+    Clear(String)
+}
+
+
 #[derive(Clone)]
 struct Domain<V> {
     values: Vec<V>
@@ -19,7 +27,6 @@ impl<V: fmt::Debug> fmt::Debug for Domain<V> {
     }
 }
 
-type Variables<'a, V> = HashMap<String, Option<&'a V>>;
 
 /// Returns all possible Updates for next assignements, prepended with
 /// a Clear to ensure the variable is unset before when leaving the branch.
@@ -43,17 +50,6 @@ fn assign_next<'a,'b, V>(assign: &'b Variables<'a, V>, domain: &'a Domain<V>)
     }
 }
 
-/// Check if any constraint is violated
-fn check_consistency<'a, V>(assign: &'a Variables<'a, V>, constraint: fn(&Variables<'a,V>) -> bool) -> bool {
-    constraint(assign)
-}
-
-enum Assignment<'a, V> {
-    Update(String, &'a V),
-    Clear(String)
-}
-
-
 /// Visit all possible solutions, using a stack.
 fn solve_all<'a, V: Clone + fmt::Debug>(mut assign: Variables<'a, V>, domain: &'a Domain<V>, is_valid: fn(&Variables<'a,V>) -> bool) 
     -> Vec<Variables<'a, V>> 
@@ -110,5 +106,24 @@ mod tests {
 
         assert_eq!(solve_all(assign, &domain, constraint), solutions);
     }
+
+    #[test]
+    fn test_solver_find_pairs_with_initial() {
+        use super::*;
+        // Find all pairs of two differents
+        let assign: Variables<i32> = [
+            ("Left".to_string(), None), 
+            ("Right".to_string(), Some(&2)),
+            ].iter().cloned().collect();
+        let domain = Domain::new(vec![1,2,3]);
+        let constraint = |assign: &Variables<i32>| {
+            assign.get("Left").unwrap() == assign.get("Right").unwrap()
+        };
+        let solutions: Vec<Variables<i32>> = vec![
+            [("Left".to_string(), Some(&2)), ("Right".to_string(), Some(&2)),].iter().cloned().collect(),
+        ];
+
+        assert_eq!(solve_all(assign, &domain, constraint), solutions);
+     }
 }