diff --git a/SLS_C/include/tests/tests.h b/SLS_C/include/tests/tests.h
index 023330a..0164821 100644
--- a/SLS_C/include/tests/tests.h
+++ b/SLS_C/include/tests/tests.h
@@ -7,12 +7,24 @@
 #define SLS_TESTS_H
 
 #include <stdint.h>
+#include "../sls/sls_errors.h"
 
 const char *TEST_FILE_NAME = "TEST_FILE.SLS";
 
+typedef enum {
+    TEST_ERROR,
+    TEST_LOGIC_FAILED,
+    TEST_ERROR_FAILED,
+    TEST_SUCCESS,
+} TestResultType;
+
 typedef struct {
     const char *name;
     uint8_t success;
+    union {
+        const char *message;
+        SlsError error;
+    };
 } TestResult;
 
 typedef struct {
diff --git a/SLS_C/tests/lexer_tests.c b/SLS_C/tests/lexer_tests.c
index 548c61a..4e1fd2e 100644
--- a/SLS_C/tests/lexer_tests.c
+++ b/SLS_C/tests/lexer_tests.c
@@ -12,10 +12,16 @@
 
 static const size_t NUM_OF_TESTS = 1;
 
-static LexerInfo start_up_test(const char *code) {
+typedef struct {
+    TestResult result;
     LexerInfo lexer_info;
-    lexer_init(&lexer_info, TEST_FILE_NAME, code);
-    return lexer_info;
+} LexerTest;
+
+static LexerTest start_up_test(const char *test_name, const char *test_code) {
+    LexerTest test = (LexerTest) {
+        .result = (TestResult) { .name = test_name, .success = 0 } };
+    lexer_init(&test.lexer_info, TEST_FILE_NAME, test_code);
+    return test;
 }
 
 static void clean_up_test(LexerResult result) {
@@ -23,21 +29,46 @@ static void clean_up_test(LexerResult result) {
         clean_token_result(result.result);
 }
 
-static TestResult test_add_statement() {
-    TestResult test_result = (TestResult){ .name = "test_add_statement", .success = 0 };
-    LexerInfo lexer_info = start_up_test("3 4 +");
-
-    LexerResult result = lexical_analysis(&lexer_info);
-
-    if (result.type == SLS_ERROR) {
-        clean_up_test(result);
-        return test_result;
-    }
-    // TODO: Finish Test
-
+static TestResult logic_fail_test(LexerTest test, LexerResult result, const char *message) {
     clean_up_test(result);
-    test_result.success = 1;
-    return test_result;
+    test.result.success = 0;
+    test.result.message = message;
+    return test.result;
+}
+
+static TestResult error_fail_test(LexerTest test, LexerResult result, SlsError error) {
+    clean_up_test(result);
+    test.result.success = 0;
+    test.result.error = error;
+    return test.result;
+}
+
+static TestResult pass_test(LexerTest test, LexerResult result) {
+    clean_up_test(result);
+    test.result.success = 1;
+    return test.result;
+}
+
+static TestResult test_add_statement() {
+    LexerTest test = start_up_test("test_add_statement", "3 4 +");
+
+    LexerResult result = lexical_analysis(&test.lexer_info);
+
+    if (result.type == SLS_ERROR)
+        return fail_test(test, result, result.error.message);
+
+    LexerTokenResult *head = result.result;
+
+    if (head->type == SLS_ERROR)
+        return fail_test(test, result, result.error.message);
+    if (head->result.type != TOKEN_INTEGER)
+        return fail_test(test, result);
+    if (head->result.integer_literal.type != INTEGER_I64)
+        return fail_test(test, result);
+    if (head->result.integer_literal.value != 3)
+        return fail_test(test, result);
+
+    return pass_test(test, result);
 }
 
 TestsReport run_lexer_tests() {