diff --git a/ortools/sat/csharp/SatSolverTests.cs b/ortools/sat/csharp/SatSolverTests.cs
index 80a7905dbf..6cded20354 100644
--- a/ortools/sat/csharp/SatSolverTests.cs
+++ b/ortools/sat/csharp/SatSolverTests.cs
@@ -13,8 +13,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.Text;
 using Xunit;
 using Google.OrTools.Sat;
+using Xunit.Abstractions;
 
 public class SolutionCounter : CpSolverSolutionCallback
 {
@@ -43,58 +45,75 @@ public class SolutionCounter : CpSolverSolutionCallback
 
 public class SolutionDivisionCounter : SolutionCounter
 {
-    public SolutionDivisionCounter(int result, IntVar a, IntVar b) : base()
+    public SolutionDivisionCounter(int result, IntVar a, IntVar b, ITestOutputHelper output)
     {
         result_ = result;
         a_ = a;
         b_ = b;
+        output_ = output;
     }
 
     public override void OnSolutionCallback()
     {
         base.OnSolutionCallback();
+
+        var solutionVariablesReport = new StringBuilder();
         foreach (IntVar v in new IntVar[] { a_, b_ })
         {
-            Console.Write($"{v.ToString()}={Value(v)} ");
+            solutionVariablesReport.Append($"{v}={Value(v)} ");
         }
-        Console.WriteLine();
+        solutionVariablesReport.AppendLine();
+        output_.WriteLine(solutionVariablesReport.ToString());
         Assert.Equal(result_, Value(a_) / Value(b_));
     }
 
-    private int result_;
-    private IntVar a_;
-    private IntVar b_;
+    private readonly int result_;
+    private readonly IntVar a_;
+    private readonly IntVar b_;
+    private readonly ITestOutputHelper output_;
 }
 
 public class SolutionModuloCounter : SolutionCounter
 {
-    public SolutionModuloCounter(int result, IntVar a, IntVar b) : base()
+    public SolutionModuloCounter(int result, IntVar a, IntVar b, ITestOutputHelper output)
     {
         result_ = result;
         a_ = a;
         b_ = b;
+        output_ = output;
     }
 
     public override void OnSolutionCallback()
     {
         base.OnSolutionCallback();
+
+        var solutionVariablesReport = new StringBuilder();
         foreach (IntVar v in new IntVar[] { a_, b_ })
         {
-            Console.Write($"{v.ToString()}={Value(v)} ");
+            solutionVariablesReport.Append($"{v}={Value(v)} ");
         }
-        Console.WriteLine();
+        solutionVariablesReport.AppendLine();
+        output_.WriteLine(solutionVariablesReport.ToString());
         Assert.Equal(result_, Value(a_) % Value(b_));
     }
 
-    private int result_;
-    private IntVar a_;
-    private IntVar b_;
+    private readonly int result_;
+    private readonly IntVar a_;
+    private readonly IntVar b_;
+    private readonly ITestOutputHelper output_;
 }
 
 namespace Google.OrTools.Tests
 {
 public class SatSolverTest
 {
+    private readonly ITestOutputHelper output_;
+
+    public SatSolverTest(ITestOutputHelper output)
+    {
+        this.output_ = output;
+    }
+
     static IntegerVariableProto NewIntegerVariable(long lb, long ub)
     {
         IntegerVariableProto var = new IntegerVariableProto();
@@ -278,12 +297,12 @@ public class SatSolverTest
         model.Add(delta == x - 5);
         model.AddMultiplicationEquality(squaredDelta, new IntVar[] { delta, delta });
         model.Minimize(squaredDelta);
-        // Console.WriteLine("model = " + model.Model.ToString());
+        // output_.WriteLine("model = " + model.Model);
 
         CpSolver solver = new CpSolver();
         CpSolverStatus status = solver.Solve(model);
         CpSolverResponse response = solver.Response;
-        Console.WriteLine("response = " + response.ToString());
+        output_.WriteLine($"response = {response}");
 
         Assert.Equal(CpSolverStatus.Optimal, status);
 
@@ -332,7 +351,7 @@ public class SatSolverTest
         model.AddDivisionEquality(3, v1, v2);
         // Console.WriteLine(model.Model);
 
-        SolutionDivisionCounter solution_callback = new SolutionDivisionCounter(3, v1, v2);
+        SolutionDivisionCounter solution_callback = new SolutionDivisionCounter(3, v1, v2, output_);
 
         CpSolver solver = new CpSolver();
         // Tell the solver to search for all solutions.
@@ -357,7 +376,7 @@ public class SatSolverTest
         model.AddModuloEquality(3, v1, v2);
         // Console.WriteLine(model.Model);
 
-        SolutionModuloCounter solution_callback = new SolutionModuloCounter(3, v1, v2);
+        SolutionModuloCounter solution_callback = new SolutionModuloCounter(3, v1, v2, output_);
 
         CpSolver solver = new CpSolver();
         // Tell the solver to search for all solutions.
@@ -390,7 +409,7 @@ public class SatSolverTest
         model.Minimize(LinearExpr.WeightedSum(vars, coeffs));
         watch.Stop();
         var elapsedMs = watch.ElapsedMilliseconds;
-        Console.WriteLine($"Long: Elapsed time {elapsedMs}");
+        output_.WriteLine($"Long: Elapsed time {elapsedMs}");
     }
 
     [Fact]
@@ -410,7 +429,7 @@ public class SatSolverTest
         model.Minimize(LinearExpr.WeightedSum(vars, coeffs));
         watch.Stop();
         var elapsedMs = watch.ElapsedMilliseconds;
-        Console.WriteLine($"Int: Elapsed time {elapsedMs}");
+        output_.WriteLine($"Int: Elapsed time {elapsedMs}");
     }
 
     [Fact]
@@ -428,7 +447,7 @@ public class SatSolverTest
         model.Minimize(LinearExpr.Sum(exprs));
         watch.Stop();
         var elapsedMs = watch.ElapsedMilliseconds;
-        Console.WriteLine($"Exprs: Elapsed time {elapsedMs}");
+        output_.WriteLine($"Exprs: Elapsed time {elapsedMs}");
     }
 
     [Fact]
@@ -453,13 +472,13 @@ public class SatSolverTest
         model.Minimize(obj);
         watch.Stop();
         var elapsedMs = watch.ElapsedMilliseconds;
-        Console.WriteLine($"Proto: Elapsed time {elapsedMs}");
+        output_.WriteLine($"Proto: Elapsed time {elapsedMs}");
     }
 
     [Fact]
     public void LinearExprStaticCompileTest()
     {
-        Console.WriteLine("LinearExprStaticCompileTest");
+        output_.WriteLine("LinearExprStaticCompileTest");
         CpModel model = new CpModel();
         IntVar v1 = model.NewIntVar(-10, 10, "v1");
         IntVar v2 = model.NewIntVar(-10, 10, "v2");
@@ -468,29 +487,29 @@ public class SatSolverTest
         long[] c1 = new long[] { 2L, 4L };
         int[] c2 = new int[] { 2, 4 };
         LinearExpr e1 = LinearExpr.Sum(new IntVar[] { v1, v2 });
-        Console.WriteLine(e1.ToString());
+        output_.WriteLine(e1.ToString());
         LinearExpr e2 = LinearExpr.Sum(new ILiteral[] { b1, b2 });
-        Console.WriteLine(e2.ToString());
+        output_.WriteLine(e2.ToString());
         LinearExpr e3 = LinearExpr.Sum(new BoolVar[] { b1, b2 });
-        Console.WriteLine(e3.ToString());
+        output_.WriteLine(e3.ToString());
         LinearExpr e4 = LinearExpr.WeightedSum(new IntVar[] { v1, v2 }, c1);
-        Console.WriteLine(e4.ToString());
+        output_.WriteLine(e4.ToString());
         LinearExpr e5 = LinearExpr.WeightedSum(new ILiteral[] { b1, b2 }, c1);
-        Console.WriteLine(e5.ToString());
+        output_.WriteLine(e5.ToString());
         LinearExpr e6 = LinearExpr.WeightedSum(new BoolVar[] { b1, b2 }, c1);
-        Console.WriteLine(e6.ToString());
+        output_.WriteLine(e6.ToString());
         LinearExpr e7 = LinearExpr.WeightedSum(new IntVar[] { v1, v2 }, c2);
-        Console.WriteLine(e7.ToString());
+        output_.WriteLine(e7.ToString());
         LinearExpr e8 = LinearExpr.WeightedSum(new ILiteral[] { b1, b2 }, c2);
-        Console.WriteLine(e8.ToString());
+        output_.WriteLine(e8.ToString());
         LinearExpr e9 = LinearExpr.WeightedSum(new BoolVar[] { b1, b2 }, c2);
-        Console.WriteLine(e9.ToString());
+        output_.WriteLine(e9.ToString());
     }
 
     [Fact]
     public void LinearExprBuilderCompileTest()
     {
-        Console.WriteLine("LinearExprBuilderCompileTest");
+        output_.WriteLine("LinearExprBuilderCompileTest");
         CpModel model = new CpModel();
         IntVar v1 = model.NewIntVar(-10, 10, "v1");
         IntVar v2 = model.NewIntVar(-10, 10, "v2");
@@ -499,155 +518,155 @@ public class SatSolverTest
         long[] c1 = new long[] { 2L, 4L };
         int[] c2 = new int[] { 2, 4 };
         LinearExpr e1 = LinearExpr.NewBuilder().AddSum(new IntVar[] { v1, v2 });
-        Console.WriteLine(e1.ToString());
+        output_.WriteLine(e1.ToString());
         LinearExpr e2 = LinearExpr.NewBuilder().AddSum(new ILiteral[] { b1, b2 });
-        Console.WriteLine(e2.ToString());
+        output_.WriteLine(e2.ToString());
         LinearExpr e3 = LinearExpr.NewBuilder().AddSum(new BoolVar[] { b1, b2 });
-        Console.WriteLine(e3.ToString());
+        output_.WriteLine(e3.ToString());
         LinearExpr e4 = LinearExpr.NewBuilder().AddWeightedSum(new IntVar[] { v1, v2 }, c1);
-        Console.WriteLine(e4.ToString());
+        output_.WriteLine(e4.ToString());
         LinearExpr e5 = LinearExpr.NewBuilder().AddWeightedSum(new ILiteral[] { b1, b2 }, c1);
-        Console.WriteLine(e5.ToString());
+        output_.WriteLine(e5.ToString());
         LinearExpr e6 = LinearExpr.NewBuilder().AddWeightedSum(new BoolVar[] { b1, b2 }, c1);
-        Console.WriteLine(e6.ToString());
+        output_.WriteLine(e6.ToString());
         LinearExpr e7 = LinearExpr.NewBuilder().AddWeightedSum(new IntVar[] { v1, v2 }, c2);
-        Console.WriteLine(e7.ToString());
+        output_.WriteLine(e7.ToString());
         LinearExpr e8 = LinearExpr.NewBuilder().AddWeightedSum(new ILiteral[] { b1, b2 }, c2);
-        Console.WriteLine(e8.ToString());
+        output_.WriteLine(e8.ToString());
         LinearExpr e9 = LinearExpr.NewBuilder().AddWeightedSum(new BoolVar[] { b1, b2 }, c2);
-        Console.WriteLine(e9.ToString());
+        output_.WriteLine(e9.ToString());
         LinearExpr e10 = LinearExpr.NewBuilder().Add(v1);
-        Console.WriteLine(e10.ToString());
+        output_.WriteLine(e10.ToString());
         LinearExpr e11 = LinearExpr.NewBuilder().Add(b1);
-        Console.WriteLine(e11.ToString());
+        output_.WriteLine(e11.ToString());
         LinearExpr e12 = LinearExpr.NewBuilder().Add(b1.Not());
-        Console.WriteLine(e12.ToString());
+        output_.WriteLine(e12.ToString());
         LinearExpr e13 = LinearExpr.NewBuilder().AddTerm(v1, -1);
-        Console.WriteLine(e13.ToString());
+        output_.WriteLine(e13.ToString());
         LinearExpr e14 = LinearExpr.NewBuilder().AddTerm(b1, -1);
-        Console.WriteLine(e14.ToString());
+        output_.WriteLine(e14.ToString());
         LinearExpr e15 = LinearExpr.NewBuilder().AddTerm(b1.Not(), -2);
-        Console.WriteLine(e15.ToString());
+        output_.WriteLine(e15.ToString());
     }
 
     [Fact]
     public void LinearExprIntVarOperatorTest()
     {
-        Console.WriteLine("LinearExprIntVarOperatorTest");
+        output_.WriteLine("LinearExprIntVarOperatorTest");
         CpModel model = new CpModel();
         IntVar v = model.NewIntVar(-10, 10, "v");
         LinearExpr e = v * 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 * v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v + 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 + v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = -v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 1 - v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v - 1;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
     }
 
     [Fact]
     public void LinearExprBoolVarOperatorTest()
     {
-        Console.WriteLine("LinearExprBoolVarOperatorTest");
+        output_.WriteLine("LinearExprBoolVarOperatorTest");
         CpModel model = new CpModel();
         BoolVar v = model.NewBoolVar("v");
         LinearExpr e = v * 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 * v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v + 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 + v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = -v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 1 - v;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v - 1;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
     }
 
     [Fact]
     public void TrueLiteralAsExpressionTest()
     {
-        Console.WriteLine("TrueLiteralAsExpressionTest");
+        output_.WriteLine("TrueLiteralAsExpressionTest");
         CpModel model = new CpModel();
         ILiteral v = model.TrueLiteral();
         LinearExpr e = v.AsExpr() * 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 * v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.AsExpr() + 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 + v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = -v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 1 - v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.AsExpr() - 1;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
     }
 
     [Fact]
     public void FalseLiteralAsExpressionTest()
     {
-        Console.WriteLine("FalseLiteralAsExpressionTest");
+        output_.WriteLine("FalseLiteralAsExpressionTest");
         CpModel model = new CpModel();
         ILiteral v = model.FalseLiteral();
         LinearExpr e = v.AsExpr() * 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 * v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.AsExpr() + 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 + v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = -v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 1 - v.AsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.AsExpr() - 1;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
     }
 
     [Fact]
     public void LinearExprNotBoolVarOperatorTest()
     {
-        Console.WriteLine("LinearExprBoolVarNotOperatorTest");
+        output_.WriteLine("LinearExprBoolVarNotOperatorTest");
         CpModel model = new CpModel();
         ILiteral v = model.NewBoolVar("v");
         LinearExpr e = v.NotAsExpr() * 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 * v.NotAsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.NotAsExpr() + 2;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 2 + v.NotAsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.NotAsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = -v.NotAsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = 1 - v.NotAsExpr();
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
         e = v.NotAsExpr() - 1;
-        Console.WriteLine(e);
+        output_.WriteLine(e.ToString());
     }
     [Fact]
     public void ExportModel()
@@ -658,7 +677,7 @@ public class SatSolverTest
         model.Add(-100000 <= v1 + 2 * v2 <= 100000);
         model.Minimize(v1 - 2 * v2);
         Assert.True(model.ExportToFile("test_model_dotnet.pbtxt"));
-        Console.WriteLine("Model written to file");
+        output_.WriteLine("Model written to file");
     }
 
     [Fact]
@@ -696,13 +715,13 @@ public class SatSolverTest
         CpModelProto model = Google.Protobuf.JsonParser.Default.Parse<CpModelProto>(model_str);
         SolveWrapper solve_wrapper = new SolveWrapper();
         CpSolverResponse response = solve_wrapper.Solve(model);
-        Console.WriteLine(response);
+        output_.WriteLine(response.ToString());
     }
 
     [Fact]
     public void CaptureLog()
     {
-        Console.WriteLine("CaptureLog test");
+        output_.WriteLine("CaptureLog test");
         CpModel model = new CpModel();
         IntVar v1 = model.NewIntVar(-10, 10, "v1");
         IntVar v2 = model.NewIntVar(-10, 10, "v2");
@@ -716,7 +735,7 @@ public class SatSolverTest
         CpSolver solver = new CpSolver();
         solver.StringParameters = "log_search_progress:true log_to_stdout:false";
         string log = "";
-        solver.SetLogCallback(message => log += message + "\n");
+        solver.SetLogCallback(message => log += $"{message}\n");
         solver.Solve(model);
         Assert.NotEmpty(log);
         Assert.Contains("OPTIMAL", log);
@@ -725,7 +744,7 @@ public class SatSolverTest
     [Fact]
     public void TestInterval()
     {
-        Console.WriteLine("TestInterval test");
+        output_.WriteLine("TestInterval test");
         CpModel model = new CpModel();
         IntVar v = model.NewIntVar(-10, 10, "v");
         IntervalVar i = model.NewFixedSizeIntervalVar(v, 3, "i");