Add formatDetection unit-test for 3DS importer

test/unit/ut3DSImportExport.cpp

@@ -66,3 +66,11 @@ public:
 TEST_F( ut3DSImportExport, import3DSFromFileTest ) {
     EXPECT_TRUE( importerTest() );
 }
+
+TEST_F( ut3DSImportExport, import3DSformatdetection) {
+    ::Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/3DS/testFormatDetection", aiProcess_ValidateDataStructure);
+
+    EXPECT_NE(nullptr, scene);
+}
+