test: cover initial solutions for SCIP

src/solvers/scip.rs

@@ -185,6 +185,7 @@ impl Solution for SCIPSolved {
 mod tests {
     use crate::{
         constraint, variable, variables, CardinalityConstraintSolver, Solution, SolverModel,
+        WithInitialSolution,
     };
 
     use super::scip;
@@ -203,6 +204,35 @@ mod tests {
         assert_eq!((solution.value(x), solution.value(y)), (0.5, 3.))
     }
 
+    #[test]
+    fn can_solve_with_initial_solution() {
+        // Solve problem initially
+        let mut vars = variables!();
+        let x = vars.add(variable().clamp(0, 2));
+        let y = vars.add(variable().clamp(1, 3));
+        let solution = vars
+            .maximise(x + y)
+            .using(scip)
+            .with((2 * x + y) << 4)
+            .solve()
+            .unwrap();
+        // Recreate same problem with initial values slightly off
+        let initial_x = solution.value(x) - 0.1;
+        let initial_y = solution.value(x) - 1.0;
+        let mut vars = variables!();
+        let x = vars.add(variable().clamp(0, 2));
+        let y = vars.add(variable().clamp(1, 3));
+        let solution = vars
+            .maximise(x + y)
+            .using(scip)
+            .with((2 * x + y) << 4)
+            .with_initial_solution([(x, initial_x), (y, initial_y)])
+            .solve()
+            .unwrap();
+
+        assert_eq!((solution.value(x), solution.value(y)), (0.5, 3.))
+    }
+
     #[test]
     fn can_solve_with_equality() {
         let mut vars = variables!();