diff --git a/spec/test_d_lexer.d b/spec/test_d_lexer.d
index a2bb5ee..80269f0 100644
--- a/spec/test_d_lexer.d
+++ b/spec/test_d_lexer.d
@@ -1,3 +1,6 @@
+import testparser;
+import std.stdio;
+
 int main()
 {
     return 0;
@@ -5,5 +8,43 @@ int main()
 
 unittest
 {
-    assert(true);
+    alias DCP = Testparser.Decoder.DecodedCodePoint;
+    string inputstring = "5+\n 66";
+    const(ubyte) * input = cast(const(ubyte) *)inputstring.ptr;
+    size_t input_length = inputstring.length;
+    DCP dcp;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP('5', 1u));
+    input += dcp.code_point_length;
+    input_length -= dcp.code_point_length;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP('+', 1u));
+    input += dcp.code_point_length;
+    input_length -= dcp.code_point_length;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP('\n', 1u));
+    input += dcp.code_point_length;
+    input_length -= dcp.code_point_length;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP(' ', 1u));
+    input += dcp.code_point_length;
+    input_length -= dcp.code_point_length;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP('6', 1u));
+    input += dcp.code_point_length;
+    input_length -= dcp.code_point_length;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP('6', 1u));
+    input += dcp.code_point_length;
+    input_length -= dcp.code_point_length;
+    dcp = Testparser.Decoder.decode_code_point(input, input_length);
+    assert(dcp == DCP(Testparser.Decoder.CODE_POINT_EOF, 0u));
+}
+
+unittest
+{
+    alias LT = Testparser.Lexer.LexedToken;
+    string input = "5 + 4 * \n677 + 567";
+    Testparser.Lexer lexer = new Testparser.Lexer(cast(const(ubyte) *)input.ptr, input.sizeof);
+    //assert(lexer.lex_token() == LT(0, 0, Testparser.TOKEN_INT));
 }