Initial scaffold: Makefile, stub malloc/free/realloc, test harness

Build system produces libft_malloc_$HOSTTYPE.so shared library with
Libft (NOMALLOC=1) as dependency. Stub functions print their name
and return NULL. Test runner compares system malloc vs LD_PRELOAD
output using write(2) to avoid stdio interference.

2 files changed, 86 insertions, 0 deletions

diff --git a/tests/Makefile b/tests/Makefile
new file mode 100644
index 0000000..04d7c1f
--- /dev/null
+++ b/tests/Makefile
@@ -0,0 +1,40 @@
+CC = cc
+CFLAGS = -Wall -Wextra -Werror $(EXTRA)
+
+SRCDIR = src
+OBJDIR = obj
+BINDIR = bin
+
+NAME = $(BINDIR)/test
+
+SRCS = main.c
+
+OBJS = $(SRCS:%.c=$(OBJDIR)/%.o)
+
+MALLOC_LIB = ../lib/libft_malloc.so
+
+$(NAME): $(OBJS) | $(BINDIR)
+	$(CC) $(CFLAGS) -o $@ $(OBJS)
+
+all: $(NAME)
+
+$(OBJDIR)/%.o: $(SRCDIR)/%.c | $(OBJDIR)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(OBJDIR):
+	mkdir -p $(OBJDIR)
+
+$(BINDIR):
+	mkdir -p $(BINDIR)
+
+test: $(NAME)
+	@echo "=== system malloc ==="
+	@$(NAME)
+	@echo ""
+	@echo "=== ft_malloc ==="
+	@LD_PRELOAD=$(MALLOC_LIB) $(NAME)
+
+clean:
+	rm -rf $(OBJDIR) $(BINDIR)
+
+.PHONY: all test clean
diff --git a/tests/src/main.c b/tests/src/main.c
new file mode 100644
index 0000000..0ded605
--- /dev/null
+++ b/tests/src/main.c
@@ -0,0 +1,46 @@
+/**
+ * @file   main.c
+ * @brief  Smoke test — call malloc once and print the returned pointer.
+ *
+ * Uses write(2) instead of printf to avoid stdio calling malloc
+ * internally, which would pollute output under LD_PRELOAD.
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+/** @brief Write the hex representation of @p ptr to stdout. */
+static void
+_s_put_ptr (void *ptr)
+{
+  const char hex[] = "0123456789abcdef";
+  char buf[20];
+  unsigned long v = (unsigned long)ptr;
+  int i;
+
+  if (!ptr)
+    {
+      write (1, "(nil)", 5);
+      return;
+    }
+  i = (int)sizeof (buf);
+  while (v)
+    {
+      buf[--i] = hex[v % 16];
+      v /= 16;
+    }
+  buf[--i] = 'x';
+  buf[--i] = '0';
+  write (1, buf + i, (size_t)(sizeof (buf) - i));
+}
+
+int
+main (void)
+{
+  void *p = malloc (42);
+  write (1, "malloc(42) = ", 13);
+  _s_put_ptr (p);
+  write (1, "\n", 1);
+  free (p);
+  return (0);
+}