Remove "empty" partition from CountBase initialization

We shouldn't be assuming that an empty partition will be used by the
user, so we shouldn't initialize all CountBase instances with the empty
partition in the config.

src/CountBase.ts

@@ -157,11 +157,7 @@ export async function createCountBase<K>(
   const configData: CountBaseConfig = {
     type: BaseType.CountBase,
     bucketSize: Math.floor(bucketSize),
-    partitions: {
-      '': {
-        length: 0
-      }
-    }
+    partitions: {}
   }
   await setConfig(memlet, dbName, configData)
 

test/CountBase.test.ts

@@ -33,18 +33,21 @@ describe('CountBase baselet', function () {
     const expectedTest: CountBaseConfig = {
       type: BaseType.CountBase,
       bucketSize: options.bucketSize,
-      partitions: {
-        '': {
-          length: 0
-        }
-      }
+      partitions: {}
     }
     countbaseDb = await createCountBase(memlet, options)
     expect(await getConfig(memlet, options.name)).eql(expectedTest)
   })
   it('empty data', async function () {
+    const length = await countbaseDb.length(partitionName)
+    expect(length).equal(0)
+
     const [data] = await countbaseDb.query(partitionName, 0)
     expect(data).equal(undefined)
+
+    const dump = await countbaseDb.dumpData()
+    expect(dump).keys(['config', 'data'])
+    expect(dump.data).deep.equals({})
   })
   it('insert data', async function () {
     for (let i = 0; i < dataSet.length; i++) {
@@ -79,7 +82,7 @@ describe('CountBase baselet', function () {
   it('dumpData', async () => {
     const dump = await countbaseDb.dumpData()
     expect(dump).keys(['config', 'data'])
-    expect(dump.data).keys(['', partitionName])
+    expect(dump.data).keys([partitionName])
     expect(dump.data[partitionName]).length(dataSet.length)
   })
 })