written structure and tests for lexer, missing

implementation

test/lexer.cpp

@@ -0,0 +1,35 @@
+#include "lexer/lexer.hpp"
+
+#include "token/type.hpp"
+
+#include <doctest.h>
+#include <string>
+
+TEST_CASE("next token") {
+    struct test {
+        token::type expectedType;
+        std::string expectedLiteral;
+    };
+
+    std::string input = "=+(){},;";
+
+    lexer::lexer l{};
+
+    test tests[] = {
+        {token::type::ASSIGN, "="},
+        {token::type::PLUS, "+"},
+        {token::type::LPAREN, "("},
+        {token::type::RPAREN, ")"},
+        {token::type::LBRACE, "{"},
+        {token::type::RBRACE, "}"},
+        {token::type::COMMA, ","},
+        {token::type::SEMICOLON, ";"},
+        {token::type::EOF_, ""},
+    };
+
+    for (const auto& t : tests) {
+        token::token tok = l.next_token();
+        CHECK(tok.type == t.expectedType);
+        CHECK(tok.literal == t.expectedLiteral);
+    }
+};