test: add new crypto tests

Add new tests according to the discussion in issue nodejs#25509.

Author: thinred

test/simple/test-crypto.js

@@ -25,6 +25,7 @@
 var common = require('../common');
 var assert = require('assert');
 var util = require('util');
+var spawn = require('child_process').spawn;
 
 try {
   var crypto = require('crypto');
@@ -855,6 +856,40 @@ var p = 'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74' +
 var bad_dh = crypto.createDiffieHellman(p, 'hex');
 assert.equal(bad_dh.verifyError, constants.DH_NOT_SUITABLE_GENERATOR);
 
+function node_output(code, args, env, cb) {
+  var out = '', err = '';
+  var p = spawn(process.execPath, [ '-e', code ].concat(args), { env: env });
+  p.stdout.on('data', function(data) { out += data; });
+  p.stderr.on('data', function(data) { err += data; });
+  p.on('close', function(code, signal) { cb(out, err, code); });
+}
+
+function no_output(out, err, code) {
+  assert.equal(out + err, '');
+  assert.equal(code, 0);
+}
+
+// test if fails on deprecated group
+node_output("require('crypto').getDiffieHellman('modp1')",
+            [], {}, function(out, err, code) {
+              assert.equal(out, '');
+              assert.ok(err.indexOf('Small DH groups disabled') > -1);
+              assert.equal(code, 1);
+            });
+
+// test if the environment variable makes it work
+node_output("require('crypto').getDiffieHellman('modp1')",
+            [], { 'ENABLE_SMALL_DH_GROUPS': '' }, no_output);
+
+// test if the cmdline switch makes it work
+node_output("require('crypto').getDiffieHellman('modp1')",
+            [ '--enable-small-dh-groups' ], {}, no_output);
+
+// test if does not fail on the next group
+node_output("require('crypto').getDiffieHellman('modp2')",
+            [], {}, no_output);
+
+
 // Test RSA encryption/decryption
 (function() {
   var input = 'I AM THE WALRUS';