Add subleveldown test

package.json

@@ -13,6 +13,7 @@
     "bytewise": "^1.1.0",
     "level-sublevel": "^6.3.11",
     "osenv": "~0.1.0",
+    "subleveldown": "^4.1.4",
     "tape": "^4.11.0"
   },
   "scripts": {

test/subleveldown.js

@@ -0,0 +1,42 @@
+var test = require('tape');
+var level = require('../');
+var path = require('path');
+var sub = require('subleveldown');
+var tmpdir = require('osenv').tmpdir();
+var datadir = path.join(tmpdir, 'level-party-' + Math.random());
+
+test('subleveldown on level-party', function (t) {
+    t.plan(9);
+
+    var a = level(datadir);
+    var b = level(datadir);
+    var asub = sub(a, 'test', { valueEncoding: 'json' });
+    var bsub = sub(b, 'test');
+    var obj = { test: Math.floor(Math.random() * 100000) };
+
+    asub.put('a', obj, function (err) {
+        t.ifError(err);
+
+        asub.get('a', function (err, value) {
+            t.ifError(err);
+            t.deepEqual(value, obj);
+        });
+        bsub.get('a', function (err, value) {
+            t.ifError(err);
+            t.deepEqual(value, JSON.stringify(obj));
+        });
+        asub.createReadStream().on('data', function (row) {
+            t.deepEqual(row.key, 'a');
+            t.deepEqual(row.value, obj);
+        });
+        bsub.createReadStream().on('data', function (row) {
+            t.deepEqual(row.key, 'a');
+            t.deepEqual(row.value, JSON.stringify(obj));
+        });
+    });
+
+    t.on('end', function () {
+        a.close();
+        b.close();
+    });
+});