txt2man: test added

Closes Homebrew/homebrew#35817.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Formula/txt2man.rb

@@ -1,20 +1,40 @@
-require 'formula'
-
 class Txt2man < Formula
-  homepage 'http://mvertes.free.fr/'
-  url 'http://mvertes.free.fr/download/txt2man-1.5.6.tar.gz'
-  sha1 'ef1392785333ea88f7e01f4f4c519ecfbdd498bd'
+  homepage "http://mvertes.free.fr/"
+  url "http://mvertes.free.fr/download/txt2man-1.5.6.tar.gz"
+  sha1 "ef1392785333ea88f7e01f4f4c519ecfbdd498bd"
 
-  depends_on 'gawk'
+  depends_on "gawk"
 
   def install
-    man1.install %W[bookman.1 src2man.1 txt2man.1]
-    bin.install %W[bookman src2man txt2man]
+    man1.install %w[bookman.1 src2man.1 txt2man.1]
+    bin.install %w[bookman src2man txt2man]
   end
 
   test do
-    system "#{bin}/txt2man", "-h"
-    system "#{bin}/src2man", "-h"
-    system "#{bin}/bookman", "-h"
+    # txt2man
+    (testpath/"test.txt").write <<-EOS.undent
+      A TITLE
+
+      blah blah blah
+    EOS
+
+    assert_match(/\.SH A TITLE/, shell_output("#{bin}/txt2man test.txt"))
+
+    # src2man
+    (testpath/"test.c").write <<-EOS.undent
+      #include <stdio.h>
+
+      /** 3
+      * main - do stuff
+      **/
+      int main(void) { return 0; }
+    EOS
+
+    assert_equal "main.3\n", shell_output("#{bin}/src2man test.c 2>&1")
+    assert File.read("main.3").include?(%q(\fBmain \fP- do stuff))
+
+    # bookman
+    system "#{bin}/bookman", "-t", "Test", "-o", "test", Dir["#{man1}/*"]
+    assert File.exist?("test")
   end
 end