Add agnostic readers

src/DotTiled.Tests/Serialization/MapReaderTests.cs

@@ -0,0 +1,50 @@
+using DotTiled.Model;
+using DotTiled.Serialization;
+
+namespace DotTiled.Tests;
+
+public partial class MapReaderTests
+{
+  public static IEnumerable<object[]> Maps => TestData.MapTests;
+  [Theory]
+  [MemberData(nameof(Maps))]
+  public void MapReaderReadMap_ValidFilesExternalTilesetsAndTemplates_ReturnsMapThatEqualsExpected(
+    string testDataFile,
+    Func<string, Map> expectedMap,
+    IReadOnlyCollection<ICustomTypeDefinition> customTypeDefinitions)
+  {
+    // Arrange
+    string[] fileFormats = [".tmx", ".tmj"];
+
+    foreach (var fileFormat in fileFormats)
+    {
+      var testDataFileWithFormat = testDataFile + fileFormat;
+      var fileDir = Path.GetDirectoryName(testDataFileWithFormat);
+      var mapString = TestData.GetRawStringFor(testDataFileWithFormat);
+      Template ResolveTemplate(string source)
+      {
+        var templateString = TestData.GetRawStringFor($"{fileDir}/{source}");
+        using var templateReader = new TemplateReader(templateString, ResolveTileset, ResolveTemplate, ResolveCustomType);
+        return templateReader.ReadTemplate();
+      }
+      Tileset ResolveTileset(string source)
+      {
+        var tilesetString = TestData.GetRawStringFor($"{fileDir}/{source}");
+        using var tilesetReader = new TilesetReader(tilesetString, ResolveTileset, ResolveTemplate, ResolveCustomType);
+        return tilesetReader.ReadTileset();
+      }
+      ICustomTypeDefinition ResolveCustomType(string name)
+      {
+        return customTypeDefinitions.FirstOrDefault(ctd => ctd.Name == name)!;
+      }
+      using var mapReader = new MapReader(mapString, ResolveTileset, ResolveTemplate, ResolveCustomType);
+
+      // Act
+      var map = mapReader.ReadMap();
+
+      // Assert
+      Assert.NotNull(map);
+      DotTiledAssert.AssertMap(expectedMap(fileFormat[1..]), map);
+    }
+  }
+}