1 files changed, 135 insertions, 0 deletions
diff --git a/tests/src/test_substr.c b/tests/src/test_substr.c
new file mode 100644
index 0000000..30e59ce
--- /dev/null
+++ b/tests/src/test_substr.c
@@ -0,0 +1,135 @@
+#include "libft.h"
+#include "test_utils.h"
+
+_S_CRASH (ft_substr_null, ft_substr (NULL, 0, 5))
+
+static void
+_s_test_substr (void)
+{
+  int i;
+  char label[128];
+
+  _s_section ("ft_substr");
+
+  /* NULL crashes */
+  _s_check ("NULL crashes", _s_crashes (_s_crash_ft_substr_null));
+
+  /* basic substring from the middle */
+  {
+    char *p = ft_substr ("hello world", 6, 5);
+    _s_check ("middle", p && strcmp (p, "world") == 0);
+    free (p);
+  }
+
+  /* from the start */
+  {
+    char *p = ft_substr ("hello", 0, 3);
+    _s_check ("from start", p && strcmp (p, "hel") == 0);
+    free (p);
+  }
+
+  /* len larger than remaining string */
+  {
+    char *p = ft_substr ("hello", 2, 100);
+    _s_check ("len > remaining", p && strcmp (p, "llo") == 0);
+    free (p);
+  }
+
+  /* start beyond string length */
+  {
+    char *p = ft_substr ("hello", 10, 5);
+    _s_check ("start > slen", p && strcmp (p, "") == 0);
+    free (p);
+  }
+
+  /* start == string length */
+  {
+    char *p = ft_substr ("hello", 5, 5);
+    _s_check ("start == slen", p && strcmp (p, "") == 0);
+    free (p);
+  }
+
+  /* empty source string */
+  {
+    char *p = ft_substr ("", 0, 10);
+    _s_check ("empty src", p && strcmp (p, "") == 0);
+    free (p);
+  }
+
+  /* len == 0 */
+  {
+    char *p = ft_substr ("hello", 0, 0);
+    _s_check ("len=0", p && strcmp (p, "") == 0);
+    free (p);
+  }
+
+  /* full string copy */
+  {
+    char *p = ft_substr ("hello", 0, 5);
+    _s_check ("full copy", p && strcmp (p, "hello") == 0);
+    free (p);
+  }
+
+  /* single character */
+  {
+    char *p = ft_substr ("hello", 4, 1);
+    _s_check ("single char", p && strcmp (p, "o") == 0);
+    free (p);
+  }
+
+  /* returns independent copy */
+  {
+    char src[] = "hello";
+    char *p = ft_substr (src, 0, 5);
+    _s_check ("independent ptr", p && p != src);
+    free (p);
+  }
+
+  /* randomized */
+  for (i = 0; i < _S_RAND_ITERS; i++)
+    {
+      int slen = rand () % 200 + 1;
+      char *src = malloc (slen + 1);
+      unsigned int start;
+      size_t len;
+      char *p;
+      int j;
+
+      if (!src)
+        continue;
+      for (j = 0; j < slen; j++)
+        src[j] = 'A' + rand () % 26;
+      src[slen] = '\0';
+
+      start = rand () % (slen + 5);
+      len = rand () % (slen + 5);
+      p = ft_substr (src, start, len);
+
+      if (start >= (unsigned int)slen)
+        {
+          snprintf (label, sizeof (label), "random start=%u >= slen=%d", start,
+                    slen);
+          _s_check (label, p && strcmp (p, "") == 0);
+        }
+      else
+        {
+          size_t remaining = slen - start;
+          size_t expected = remaining < len ? remaining : len;
+          snprintf (label, sizeof (label), "random start=%u len=%zu slen=%d",
+                    start, len, slen);
+          _s_check (label, p && strlen (p) == expected
+                               && strncmp (p, src + start, expected) == 0);
+        }
+      free (p);
+      free (src);
+    }
+}
+
+int
+main (void)
+{
+  srand (time (NULL));
+  _s_test_substr ();
+  _s_print_results ();
+  return (_s_fail != 0);
+}