diff --git a/src/stdio/popen.c b/src/stdio/popen.c
new file mode 100644
index 0000000..a373df6
--- /dev/null
+++ b/src/stdio/popen.c
@@ -0,0 +1,48 @@
+#define _POSIX_C_SOURCE 200809L
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <signal.h>
+#include "test.h"
+
+#define TEST(r, f, x, m) ( \
+	((r) = (f)) == (x) || (error("%s failed (" m ")\n", #f, r, x), 0) )
+
+#define TEST_E(f) ( \
+	(errno = 0), \
+	(f) || (error("%s failed (errno = %d)\n", #f, errno), 0) )
+
+#define TEST_S(s, x, m) ( \
+	!strcmp((s),(x)) || \
+		(error("[%s] != [%s] (%s)\n", s, x, m), 0) )
+
+static sig_atomic_t got_sig;
+
+static void handler(int sig) {
+	got_sig = 1;
+}
+
+void test_popen(void) {
+	int i;
+	char foo[6];
+	char cmd[64];
+	FILE *f;
+
+	TEST_E(f = popen("echo hello", "r"));
+	if (f) {
+		TEST_E(fgets(foo, sizeof foo, f));
+		TEST_S(foo, "hello", "child process did not say hello");
+		TEST(i, pclose(f), 0, "exit status %04x != %04x");
+	}
+
+	signal(SIGUSR1, handler);
+	snprintf(cmd, sizeof cmd, "read a ; test \"x$a\" = xhello && kill -USR1 %d", getpid());
+	TEST_E(f = popen(cmd, "w"));
+	if (f) {
+		TEST_E(fputs("hello", f) >= 0);
+		TEST(i, pclose(f), 0, "exit status %04x != %04x");
+		TEST(i, got_sig, 1, "child process did not send signal");
+	}
+	signal(SIGUSR1, SIG_DFL);
+}