libsigsegv: add test

Formula/libsigsegv.rb

@@ -1,11 +1,9 @@
-require 'formula'
-
 class Libsigsegv < Formula
   desc "Library for handling page faults in user mode"
-  homepage 'https://www.gnu.org/software/libsigsegv/'
-  url 'http://ftpmirror.gnu.org/libsigsegv/libsigsegv-2.10.tar.gz'
-  mirror 'http://ftp.gnu.org/gnu/libsigsegv/libsigsegv-2.10.tar.gz'
-  sha256 '8460a4a3dd4954c3d96d7a4f5dd5bc4d9b76f5754196aa245287553b26d2199a'
+  homepage "https://www.gnu.org/software/libsigsegv/"
+  url "http://ftpmirror.gnu.org/libsigsegv/libsigsegv-2.10.tar.gz"
+  mirror "https://ftp.gnu.org/gnu/libsigsegv/libsigsegv-2.10.tar.gz"
+  sha256 "8460a4a3dd4954c3d96d7a4f5dd5bc4d9b76f5754196aa245287553b26d2199a"
 
   bottle do
     cellar :any
@@ -24,7 +22,52 @@ def install
                           "--prefix=#{prefix}",
                           "--enable-shared"
     system "make"
-    system "make check"
-    system "make install"
+    system "make", "check"
+    system "make", "install"
+  end
+
+  test do
+    # Sourced from tests/efault1.c in tarball.
+    (testpath/"test.c").write <<-EOS.undent
+      #include "sigsegv.h"
+
+      #include <errno.h>
+      #include <fcntl.h>
+      #include <stdio.h>
+      #include <stdlib.h>
+      #include <unistd.h>
+
+      const char *null_pointer = NULL;
+      static int
+      handler (void *fault_address, int serious)
+      {
+        abort ();
+      }
+
+      int
+      main ()
+      {
+        if (open (null_pointer, O_RDONLY) != -1 || errno != EFAULT)
+          {
+            fprintf (stderr, "EFAULT not detected alone");
+            exit (1);
+          }
+
+        if (sigsegv_install_handler (&handler) < 0)
+          exit (2);
+
+        if (open (null_pointer, O_RDONLY) != -1 || errno != EFAULT)
+          {
+            fprintf (stderr, "EFAULT not detected with handler");
+            exit (1);
+          }
+
+        printf ("Test passed");
+        return 0;
+      }
+    EOS
+
+    system ENV.cc, "test.c", "-lsigsegv", "-o", "test"
+    assert_match /Test passed/, shell_output("./test")
   end
 end