INT-958 add dryrun subcommand

The "dryrun" command invokes mongodb-version-manger but skips actual start/stop.

This is useful on CI systems to ensure that a version of mongodb is available
before mocha is invoked. Specify "mongodb-runner dryrun" as the "pretest" script.

Author: kangas

lib/index.js

@@ -354,7 +354,7 @@ function configure(opts, done) {
 var exec = module.exports = exports = function(opts, done) {
   opts.action = opts.action || 'start';
 
-  if (['start', 'stop'].indexOf(opts.action) === -1) {
+  if (['dryrun', 'start', 'stop'].indexOf(opts.action) === -1) {
     done(new Error('Unknown action.'));
     return;
   }
@@ -371,6 +371,11 @@ var exec = module.exports = exports = function(opts, done) {
       return;
     }
 
+    if (opts.action === 'dryrun') {
+      done();
+      return;
+    }
+
     if (opts.action === 'start') {
       start(opts, done);
     }

test/index.test.js

@@ -2,12 +2,37 @@
 
 var run = require('../');
 var kill = require('kill-mongodb');
+var mvm = require('mongodb-version-manager');
+var assert = require('assert');
 
 describe('Test Spawning MongoDB Deployments', function() {
   before(function(done) {
     kill(done);
   });
 
+  describe('Dry Run', function() {
+    var opts = {
+      action: 'dryrun',
+      name: 'mongodb-runner-test-standalone',
+      port: 20000
+    };
+
+    it('should only invoke mongodb-version-manager', function(done) {
+      run(opts, function(err) {
+        if (err) {
+          return done(err);
+        }
+        mvm.current(function(err2, v) {
+          if (err2) {
+            return done(err2);
+          }
+          assert(v);  // ensure not null
+          done();
+        });
+      });
+    });
+  });
+
   describe('Standalone', function() {
     var opts = {
       action: 'start',

usage.txt

@@ -1,4 +1,5 @@
-Usage: mongodb-runner <start|stop> [options]
+
+Usage: mongodb-runner <start|stop|dryrun> [options]
 
 Start/stop mongodb for testing.