written structure and tests for lexer, missing

implementation

test/test.cpp

@@ -0,0 +1,20 @@
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include <doctest.h>
+
+int factorial(int number) {
+    return number <= 1 ? number : factorial(number - 1) * number;
+}
+
+TEST_CASE("fact") {
+    CHECK(factorial(1) == 1);
+    CHECK(factorial(2) == 2);
+    CHECK(factorial(3) == 6);
+    CHECK(factorial(10) == 3628800);
+}
+
+TEST_CASE("fact2") {
+    CHECK(factorial(1) == 1);
+    CHECK(factorial(2) == 2);
+    CHECK(factorial(3) == 6);
+    CHECK(factorial(10) == 3628800);
+}