xml2: add install check

pkgs/tools/text/xml/xml2/default.nix

···
   nativeBuildInputs = [ pkg-config ];
   buildInputs = [ libxml2 ];
 
+  doInstallCheck = true;
+  installCheckPhase = ''
+    runHook preInstallCheck
+
+    echo -n 'checking csv2 and 2csv...'
+    $out/bin/csv2 -f <<< $'a,b\n1,2' \
+      | $out/bin/2csv record a b \
+      | grep -qF '1,2'
+    echo ' ok'
+
+    echo -n 'checking xml2 and 2xml...'
+    $out/bin/xml2 <<< $'<a>abc</a>' \
+      | $out/bin/2xml \
+      | grep -qF '<a>abc</a>'
+    echo ' ok'
+
+    runHook postInstallCheck
+  '';
+
   meta = with lib; {
     homepage = "https://web.archive.org/web/20160515005047/http://dan.egnor.name:80/xml2";
     description = "Tools for command line processing of XML, HTML, and CSV";