diff --git a/src/client.c b/tests/client.c
similarity index 100%
rename from src/client.c
rename to tests/client.c
diff --git a/tests/index.html b/tests/index.html
new file mode 100644
index 0000000..c7a91ec
--- /dev/null
+++ b/tests/index.html
@@ -0,0 +1,3 @@
+<html>
+Welcome to the <img src=”/image.png”> example.re homepage!
+</html>
diff --git a/src/main.c b/tests/main.c
similarity index 100%
rename from src/main.c
rename to tests/main.c
diff --git a/src/server.c b/tests/server.c
similarity index 100%
rename from src/server.c
rename to tests/server.c
diff --git a/tests/test.h b/tests/test.h
new file mode 100644
index 0000000..99d59f6
--- /dev/null
+++ b/tests/test.h
@@ -0,0 +1,18 @@
+#pragma once
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define ASSERT(cond) \
+	do { \
+		if (!(cond)) { \
+			fprintf(stderr, "FAIL  %s:%d  %s\n", __FILE__, __LINE__, #cond); \
+			exit(1); \
+		} \
+	} while (0)
+
+#define ASSERT_EQ(a, b)     ASSERT((a) == (b))
+#define ASSERT_NE(a, b)     ASSERT((a) != (b))
+#define ASSERT_STR_EQ(a, b) ASSERT(strcmp((a), (b)) == 0)
+#define ASSERT_NULL(p)      ASSERT((p) == NULL)
+#define ASSERT_NOT_NULL(p)  ASSERT((p) != NULL)
diff --git a/tests/test_enchufe.c b/tests/test_enchufe.c
new file mode 100644
index 0000000..c4c521b
--- /dev/null
+++ b/tests/test_enchufe.c
@@ -0,0 +1,61 @@
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include "enchufe.h"
+#include "test.h"
+
+static void test_atob_len(void) {
+    Buffer b = atob("hello");
+    ASSERT_EQ(b.len, 5);
+}
+
+static void test_atob_contents(void) {
+    Buffer b = atob("hello");
+    ASSERT(memcmp(b.buf, "hello", 5) == 0);
+}
+
+static void test_atob_empty(void) {
+    Buffer b = atob("");
+    ASSERT_EQ(b.len, 0);
+}
+
+static void test_nuevo_valid_fd(void) {
+    FD fd = nuevo();
+    ASSERT(fd >= 0);
+    close(fd);
+}
+
+static void test_receptaculo_fields(void) {
+    IPv4 ip    = {.bytes = {127, 0, 0, 1}};
+    Port port  = htons(8080);
+    Receptaculo r = receptaculo(ip, port);
+    ASSERT_EQ(r.addr.sin_family, AF_INET);
+    ASSERT_EQ(r.addr.sin_port, port);
+    ASSERT_EQ(r.addr.sin_addr.s_addr, ip.ip);
+    ASSERT_EQ(r.addrlen, (socklen_t)sizeof(struct sockaddr_in));
+}
+
+static void test_aplasta_copies_fields(void) {
+    FD fd     = nuevo();
+    IPv4 ip   = {.bytes = {127, 0, 0, 1}};
+    Port port = htons(9090);
+    Receptaculo r = receptaculo(ip, port);
+    Enchufe e     = aplasta(fd, r);
+    ASSERT_EQ(e.fd, fd);
+    ASSERT_EQ(e.addr.sin_port, r.addr.sin_port);
+    ASSERT_EQ(e.addr.sin_addr.s_addr, r.addr.sin_addr.s_addr);
+    ASSERT_EQ(e.addrlen, r.addrlen);
+    close(fd);
+}
+
+int main(void) {
+    test_atob_len();
+    test_atob_contents();
+    test_atob_empty();
+    test_nuevo_valid_fd();
+    test_receptaculo_fields();
+    test_aplasta_copies_fields();
+    printf("test_enchufe: all tests passed\n");
+    return 0;
+}
diff --git a/tests/test_network.c b/tests/test_network.c
new file mode 100644
index 0000000..96f3ebb
--- /dev/null
+++ b/tests/test_network.c
@@ -0,0 +1,103 @@
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "enchufe.h"
+#include "test.h"
+
+#define MSG "ping"
+
+/* Bind to port 0 (OS picks a free port), return the assigned port in
+   network byte order via *out_port. */
+static Enchufe bind_ephemeral(IPv4 ip, Port *out_port) {
+    Enchufe s = enchufa(ip, htons(0));
+    amarra(s);
+
+    struct sockaddr_in actual = {0};
+    socklen_t alen            = sizeof(actual);
+    getsockname(s.fd, (struct sockaddr *)&actual, &alen);
+    *out_port = actual.sin_port; /* already network byte order */
+    return s;
+}
+
+static void test_send_recv(void) {
+    IPv4 lo  = {.bytes = {127, 0, 0, 1}};
+    Port port = 0;
+    Enchufe server = bind_ephemeral(lo, &port);
+    escucha(server, 1);
+
+    pid_t pid = fork();
+    ASSERT(pid >= 0);
+
+    if (pid == 0) {
+        Enchufe client = enchufa(lo, port);
+        conecta(client);
+        zumba(client, atob(MSG));
+        desenchufa(client);
+        exit(0);
+    }
+
+    Enchufe peer = acepta(server);
+
+    Byte raw[32] = {0};
+    Buffer buf   = {.buf = raw, .len = sizeof(raw) - 1};
+    size_t n     = recibe(peer, buf);
+
+    ASSERT_EQ(n, strlen(MSG));
+    ASSERT(memcmp(raw, MSG, n) == 0);
+
+    desenchufa(peer);
+    desenchufa(server);
+
+    int status = 0;
+    waitpid(pid, &status, 0);
+    ASSERT(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+}
+
+static void test_multi_send(void) {
+    IPv4 lo  = {.bytes = {127, 0, 0, 1}};
+    Port port = 0;
+    Enchufe server = bind_ephemeral(lo, &port);
+    escucha(server, 1);
+
+    pid_t pid = fork();
+    ASSERT(pid >= 0);
+
+    if (pid == 0) {
+        Enchufe client = enchufa(lo, port);
+        conecta(client);
+        zumba(client, atob("foo"));
+        zumba(client, atob("bar"));
+        desenchufa(client);
+        exit(0);
+    }
+
+    Enchufe peer = acepta(server);
+
+    /* Accumulate until EOF (child closes socket). */
+    Byte raw[64] = {0};
+    size_t total  = 0;
+    while (total < sizeof(raw) - 1) {
+        Buffer b = {.buf = raw + total, .len = sizeof(raw) - 1 - total};
+        size_t n  = recibe(peer, b);
+        if (n == 0) break;
+        total += n;
+    }
+
+    ASSERT(memcmp(raw, "foobar", 6) == 0);
+
+    desenchufa(peer);
+    desenchufa(server);
+
+    int status = 0;
+    waitpid(pid, &status, 0);
+    ASSERT(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+}
+
+int main(void) {
+    test_send_recv();
+    test_multi_send();
+    printf("test_network: all tests passed\n");
+    return 0;
+}