add compression test suite

package.json

@@ -34,6 +34,8 @@
     "nan": "~1.8.4"
   },
   "devDependencies": {
+    "async": "~1.0.0",
+    "delayed": "~1.0.1",
     "du": "~0.1.0",
     "faucet": "0.0.1",
     "mkfiletree": "~0.0.1",

test/compression-test.js

@@ -0,0 +1,92 @@
+/* Copyright (c) 2012-2015 LevelUP contributors
+ * See list at <https://github.com/level/leveldown#contributing>
+ * MIT License <https://github.com/level/leveldown/blob/master/LICENSE.md>
+ */
+
+var async      = require('async')
+  , du         = require('du')
+  , delayed    = require('delayed')
+  , common     = require('abstract-leveldown/testCommon')
+  , leveldown  = require('../')
+  , test       = require('tape')
+
+  , compressableData = new Buffer(Array.apply(null, Array(1024 * 100)).map(function () { return 'aaaaaaaaaa' }).join(''))
+  , multiples = 10
+  , dataSize = compressableData.length * multiples
+
+  , verify = function (location, compression, t) {
+      du(location, function (err, size) {
+        t.error(err)
+        if (compression)
+          t.ok(size < dataSize, 'on-disk size (' + size + ') is less than data size (' + dataSize + ')')
+        else
+          t.ok(size >= dataSize, 'on-disk size (' + size + ') is greater than data size (' + dataSize + ')')
+        t.end()
+      })
+    }
+
+    // close, open, close again.. 'compaction' is also performed on open()s
+  , cycle = function (db, compression, t, callback) {
+      var location = db.location
+      db.close(function (err) {
+        t.error(err)
+        db = leveldown(location)
+        db.open({ errorIfExists: false, compression: compression }, function () {
+          t.error(err)
+          db.close(function (err) {
+            t.error(err)
+            callback()
+          })
+        })
+      })
+    }
+
+test('Compression', function (t) {
+  t.test('set up', common.setUp)
+
+  t.test('test data is compressed by default (db.put())', function (t) {
+    var db = leveldown(common.location())
+    db.open(function (err) {
+      t.error(err)
+      async.forEach(
+          Array.apply(null, Array(multiples)).map(function (e, i) {
+            return [ i, compressableData ]
+          })
+        , function (args, callback) {
+            db.put.apply(db, args.concat([callback]))
+          }
+        , cycle.bind(null, db, true, t, delayed.delayed(verify.bind(null, db.location, true, t), 0.01))
+      )
+    })
+  })
+
+  t.test('test data is not compressed with compression=false on open() (db.put())', function (t) {
+    var db = leveldown(common.location())
+    db.open({ compression: false }, function (err) {
+      t.error(err)
+      async.forEach(
+          Array.apply(null, Array(multiples)).map(function (e, i) {
+            return [ i, compressableData ]
+          })
+        , function (args, callback) {
+            db.put.apply(db, args.concat([callback]))
+          }
+        , cycle.bind(null, db, false, t, delayed.delayed(verify.bind(null, db.location, false, t), 0.01))
+      )
+    })
+  })
+
+  t.test('test data is compressed by default (db.batch())', function (t) {
+    var db = leveldown(common.location())
+    db.open(function (err) {
+      t.error(err)
+      db.batch(
+          Array.apply(null, Array(multiples)).map(function (e, i) {
+            return { type: 'put', key: i, value: compressableData }
+          })
+        , cycle.bind(null, db, false, t, delayed.delayed(verify.bind(null, db.location, false, t), 0.01))
+      )
+    })
+  })
+})
+