test func "string?"

main.c

@@ -150,6 +150,7 @@ static void test_charQN();
 static void test_nullQN();
 static void test_numberQN();
 static void test_pairQN();
+static void test_stringQN();
 // Logical operators
 static void test_not();
 
@@ -163,6 +164,7 @@ void test()
     test_nullQN();
     test_numberQN();
     test_pairQN();
+    test_stringQN();
     // Logical operators
     test_not();
 
@@ -624,6 +626,82 @@ void test_pairQN()
     ))));
 }
 
+void test_stringQN()
+{
+    // (string? '())
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        NULL
+    ))));
+
+    // (string? #t)
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_new_boolean(true)
+    ))));
+
+    // (string? #f)
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_new_boolean(false)
+    ))));
+
+    // (string? #\n)
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_new_char('\n')
+    ))));
+
+    // (string? 'foo)
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_build_list(
+            2,
+            Object_new_symbol("quote"),
+            Object_new_symbol("foo")
+        )
+    ))));
+
+    // (string? "foo")
+    // #t
+    assert(Object_is_true(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_new_string("foo")
+    ))));
+
+    // (string? 123)
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_new_number(123)
+    ))));
+
+    // (string? (cons 123 456))
+    // #f
+    assert(Object_is_false(eval(Object_build_list(
+        2,
+        Object_new_symbol("string?"),
+        Object_build_list(
+            3,
+            Object_new_symbol("cons"),
+            Object_new_number(123),
+            Object_new_number(456)
+        )
+    ))));
+}
+
 void test_not()
 {
     // (not '())