feat: add some tests

EndMove.Sudoku.Solver.sln

@@ -4,6 +4,10 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{67AA5CD2-BE1
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EndMove.Sudoku.Solver.Core", "src\EndMove.Sudoku.Solver.Core\EndMove.Sudoku.Solver.Core.csproj", "{2A444DA7-B235-4419-8B31-F9A554496D8E}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "test", "test", "{F3DB57FC-878B-40EC-ABC3-0AC37DD4693F}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EndMove.Sudoku.Solver.Test", "test\EndMove.Sudoku.Solver.Test\EndMove.Sudoku.Solver.Test.csproj", "{BA84417D-96D2-4307-B804-974DF6A715F2}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -14,8 +18,13 @@ Global
 		{2A444DA7-B235-4419-8B31-F9A554496D8E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{2A444DA7-B235-4419-8B31-F9A554496D8E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{2A444DA7-B235-4419-8B31-F9A554496D8E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BA84417D-96D2-4307-B804-974DF6A715F2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BA84417D-96D2-4307-B804-974DF6A715F2}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BA84417D-96D2-4307-B804-974DF6A715F2}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BA84417D-96D2-4307-B804-974DF6A715F2}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{2A444DA7-B235-4419-8B31-F9A554496D8E} = {67AA5CD2-BE13-4741-8F70-4FE3638271E4}
+		{BA84417D-96D2-4307-B804-974DF6A715F2} = {F3DB57FC-878B-40EC-ABC3-0AC37DD4693F}
 	EndGlobalSection
 EndGlobal

src/EndMove.Sudoku.Solver.Core/Algorithms/SolverBase.cs

@@ -24,12 +24,12 @@ public abstract class SolverBase : ISolver
             }
         }
         // Check Box
-        int xSize = (col / 3) * 3, ySize = (row / 3) * 3;
+        int xSize = col - (col % 3), ySize = row - (row % 3);
-        for (int y = 0; y < 3; y++)
+        for (int y = ySize; y < ySize + 3; y++)
         {
-            for (int x = 0; x < 3; x++)
+            for (int x = xSize; x < xSize + 3; x++)
             {
-                if (board[ySize + y, xSize + x] == n)
+                if (board[y, x] == n)
                 {
                     return false;
                 }

src/EndMove.Sudoku.Solver.Core/Program.cs

@@ -63,7 +63,7 @@ namespace EndMove.Sudoku.Solver.Core
             // TODO Add time measurement
 
             ISolver solver = new BackTrackingSolver(SudokuUtils.DisplayBoard);
-            var (status, lol) = solver.Solve(store[0]);
+            var (status, lol) = solver.Solve(store[1]);
             Console.WriteLine(status);
         }
     }

test/EndMove.Sudoku.Solver.Test/EndMove.Sudoku.Solver.Test.csproj

@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="coverlet.collector" Version="6.0.0"/>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0"/>
+        <PackageReference Include="NUnit" Version="3.14.0"/>
+        <PackageReference Include="NUnit.Analyzers" Version="3.9.0"/>
+        <PackageReference Include="NUnit3TestAdapter" Version="4.5.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <Using Include="NUnit.Framework"/>
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\..\src\EndMove.Sudoku.Solver.Core\EndMove.Sudoku.Solver.Core.csproj" />
+    </ItemGroup>
+
+</Project>

test/EndMove.Sudoku.Solver.Test/SolverBaseTest.cs

@@ -0,0 +1,138 @@
+using EndMove.Sudoku.Solver.Core.Algorithms;
+
+namespace EndMove.Sudoku.Solver.Test
+{
+    public class SolverBaseTests
+    {
+        // Mock implementation of SolverBase for testing
+        private class MockSolver : SolverBase
+        {
+            public MockSolver(Action<int[,]> displayBoard) : base(displayBoard) { }
+
+            public override (bool, int[,]) Solve(int[,] board)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override (bool, int[]) Solve(int[] board)
+            {
+                throw new NotImplementedException();
+            }
+        }
+
+        // Test fixture
+        private SolverBase _solverBase;
+
+        [SetUp]
+        public void Setup()
+        {
+            // Create a mock display method (if necessary)
+            Action<int[,]> mockDisplay = (board) => { /* mock display implementation */ };
+            _solverBase = new MockSolver(mockDisplay);
+        }
+
+        [Test]
+        public void IsValid1D_ValidPlacement_ReturnsTrue()
+        {
+            // GIVEN
+            int row = 1, col = 4, n = 1;
+            int[,] board = {
+                //|--------|-------|--------|
+                { 0, 0, 1, 0, 0, 0, 1, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 1, 0, 0, 0, 1, 0, 0 },
+                { 0, 0, 0, 1, 0, 1, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 }
+                //|--------|-------|--------|
+            };
+
+            // WHEN
+            bool result = _solverBase.IsValid(board, row, col, n);
+
+            // THEN
+            Assert.That(result, Is.True, "Expected valid placement to return true.");
+        }
+
+        [Test]
+        public void IsValid1D_InvalidPlacementInColumn_ReturnsFalse()
+        {
+            // GIVEN
+            int row = 3, col = 2, n = 9;
+            int[,] board = {
+                //|--------|-------|--------|
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 9, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 }
+                //|--------|-------|--------|
+            };
+
+            // WHEN
+            bool result = _solverBase.IsValid(board, row, col, n);
+
+            // THEN
+            Assert.That(result, Is.False, "Expected invalid placement in column to return false.");
+        }
+
+        [Test]
+        public void IsValid1D_InvalidPlacementInRow_ReturnsFalse()
+        {
+            // GIVEN
+            int row = 4, col = 2, n = 9;
+            int[,] board = {
+                //|--------|-------|--------|
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 9, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 }
+                //|--------|-------|--------|
+            };
+
+            // WHEN
+            bool result = _solverBase.IsValid(board, row, col, n);
+
+            // THEN
+            Assert.That(result, Is.False, "Expected invalid placement in row to return false.");
+        }
+
+        [Test]
+        public void IsValid1D_InvalidPlacementInBox_ReturnsFalse()
+        {
+            // GIVEN
+            int row = 8, col = 5, n = 1;
+            int[,] board = {
+                //|--------|-------|--------|
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 9, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 1, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+                { 0, 0, 0, 0, 0, 0, 0, 0, 0 }
+                //|--------|-------|--------|
+            };
+
+            // WHEN
+            bool result = _solverBase.IsValid(board, row, col, n);
+
+            // THEN
+            Assert.That(result, Is.False, "Expected invalid placement in box to return false.");
+        }
+    }
+}