a weird generic migration api

gistfile1.txt

var upgrayedd = require('../index');
var test = require('tap').test;

test('error thrown on setVersion() failure', function(t) {
  upgrayedd.migrate({
    toVersion: 4,
    storage: {
      getVersion: function(cb) { cb(null, 1); },
      setVersion: function(v, cb) { cb("SETVERSION FAIL"); } 
    },
    upgrade: null
  }, function(err) {
    t.same(err, "SETVERSION FAIL", "exception from setVersion() propagated");
    t.end();
  });
});

test('error thrown on getVersion() failure', function(t) {
  upgrayedd.migrate({
    toVersion: 1,
    storage: {
      getVersion: function(cb) {
        process.nextTick(function() { cb("GETVERSION FAIL"); });
      }
    },
    upgrade: null
  }, function(err) {
    t.same(err, "GETVERSION FAIL", "exception from getVersion() propagated");
    t.end();
  });
});

test('upgrade not called if at toVersion', function(t) {
  var setVersions = [];
  upgrayedd.migrate({
    toVersion: 4,
    storage: {
      getVersion: function(cb) { cb(null, 4); },
      setVersion: function(v, cb) { setVersions.push(v); cb(null); }
    },
    upgrade: null
  }, function(err, newVersion) {
    t.same(err, null, "no error is reported");
    t.same(newVersion, 4, "upgraded to latest version");
    t.same(setVersions, [4], "setVersion set to 4");
    t.end();
  });
});

test('upgrade called multiple times if needed', function(t) {
  var version = 0;
  var upgradePath = [];
  
  upgrayedd.migrate({
    toVersion: 4,
    storage: {
      getVersion: function(cb) {
        process.nextTick(function() { cb(null, version); });
      },
      setVersion: function(newVersion, cb) {
        process.nextTick(function() {
          version = newVersion;
          upgradePath.push(version);
          cb(null);
        });
      }
    },
    upgrade: function(currVersion, maxVersion, done) {
      if (currVersion == 0) return done(null, 1);
      if (currVersion == 1) return done(null, 3);
      if (currVersion == 3) return done(null, 4);
    }
  }, function(err, newVersion) {
    t.same(err, null, "no error is reported");
    t.same(newVersion, 4, "upgraded to latest version");
    t.deepEqual(upgradePath, [0, 1, 3, 4], "upgrade path is correct");
    t.end();
  });
});