Fix passing options to abstract db.open()

compose.js

@@ -34,7 +34,7 @@ module.exports = function compose () {
         // If db is levelup, it will auto-open and call the callback. If
         // abstract-leveldown, it won't. If abstract-db (a concept), it might.
         if (callback && !isLevelup(db) && db.status === 'new') {
-          db.open(options, function (err) {
+          db.open(xtend(layer.defaults, options), function (err) {
             if (err) return callback(err)
             callback(null, db)
           })
@@ -54,7 +54,8 @@ module.exports = function compose () {
       return shell
     }
 
-    layers.push(function (db, options, callback) {
+    layers.push(function wrapped (db, options, callback) {
+      wrapped.defaults = defaults
       return layer(db, xtend(defaults, options), callback)
     })
 

test.js

@@ -10,7 +10,6 @@ var packager = function (down) {
 }
 
 // Tests copied from level-packager
-// TODO: write own tests
 
 test('packager - Level constructor has access to levelup errors', function (t) {
   function Down () {}
@@ -93,3 +92,106 @@ test('packager - Level constructor with custom options', function (t) {
   t.is(levelup._db.codec.opts.keyEncoding, 'binary')
   t.is(levelup._db.codec.opts.valueEncoding, 'binary')
 })
+
+// Own tests
+// TODO: write more
+
+test('passes defaults only to preceding layer', function (t) {
+  t.plan(12)
+
+  compose(negative, positive, { test: true }, negative)('test-location')
+  compose([negative, positive, { test: true }, negative])('test-location')
+  compose().use([negative, positive, { test: true }, negative])('test-location')
+  compose().use(negative).use(positive, { test: true }).use(negative)('test-location')
+
+  function negative (dbOrLocation, options) {
+    t.same(options, {}, 'did not get defaults')
+    return dbOrLocation
+  }
+
+  function positive (dbOrLocation, options) {
+    t.same(options, { test: true }, 'did get defaults')
+    return dbOrLocation
+  }
+})
+
+test('passes defaults only to preceding layers (in array)', function (t) {
+  t.plan(4)
+
+  compose(negative, [positive, positive], { test: true }, negative)('test-location')
+
+  function negative (dbOrLocation, options) {
+    t.same(options, {}, 'did not get defaults')
+    return dbOrLocation
+  }
+
+  function positive (dbOrLocation, options) {
+    t.same(options, { test: true }, 'did get defaults')
+    return dbOrLocation
+  }
+})
+
+test('merges defaults into preceding layers', function (t) {
+  t.plan(9)
+
+  const objects = { a: { a: 1 }, b: { b: 2 } }
+
+  compose().use([b, [ab, ab], objects.a, b], objects.b)('test-location')
+  compose().use(none).use([a, a], objects.a).use(b, objects.b)('test-location')
+
+  t.same(objects, { a: { a: 1 }, b: { b: 2 } }, 'did not mutate original objects')
+
+  function a (dbOrLocation, options) {
+    t.same(options, { a: 1 }, 'only a')
+    return dbOrLocation
+  }
+
+  function b (dbOrLocation, options) {
+    t.same(options, { b: 2 }, 'only b')
+    return dbOrLocation
+  }
+
+  function ab (dbOrLocation, options) {
+    t.same(options, { a: 1, b: 2 }, 'a and b')
+    return dbOrLocation
+  }
+
+  function none (dbOrLocation, options) {
+    t.same(options, {}, 'none')
+    return dbOrLocation
+  }
+})
+
+test('passes defaults to abstract db.open() if callback is provided', function (t) {
+  t.plan(20)
+
+  compose(lastLayer, { test: true })('test-location', onOpen)
+  compose([firstLayer, lastLayer], { test: true })('test-location', onOpen)
+  compose([[firstLayer, lastLayer], { test: false }], { test: true })('test-location', onOpen)
+
+  function firstLayer (location, options, callback) {
+    t.is(callback, undefined, 'only last layer receives callback')
+    return location
+  }
+
+  function lastLayer (location, options, callback) {
+    t.is(location, 'test-location', 'got location')
+    t.same(options, { test: true }, 'got options')
+    t.is(callback, onOpen, 'got callback')
+
+    // Mock abstract-leveldown
+    return {
+      status: 'new',
+      mocked: true,
+      open: function (options, callback) {
+        t.same(options, { test: true }, 'got open() options')
+        process.nextTick(callback)
+      }
+    }
+  }
+
+  function onOpen (err, db) {
+    t.ifError(err, 'no open error')
+    t.is(db.mocked, true, 'got db')
+  }
+})