refactor: check for negative balances

packages/core-database-postgres/lib/connection.js

@@ -113,16 +113,26 @@ module.exports = class PostgresConnection extends ConnectionInterface {
     if (!lastBlock) {
       errors.push('Last block is not available')
     } else {
-      const numberOfBlocks = await this.__numberOfBlocks()
+      const { count: numberOfBlocks } = await this.db.blocks.count()
 
       // Last block height equals the number of stored blocks
       if (lastBlock.data.height !== +numberOfBlocks) {
         errors.push(`Last block height: ${lastBlock.data.height.toLocaleString()}, number of stored blocks: ${numberOfBlocks}`)
       }
     }
 
-    const blockStats = await this.__blockStats()
-    const transactionStats = await this.__transactionStats()
+    const blockStats = await this.db.blocks.statistics()
+    const transactionStats = await this.db.transactions.statistics()
+    const { count: negativeBalances } = await this.db.wallets.findNegativeBalances()
+    const { count: negativeVoteBalances } = await this.db.wallets.findNegativeVoteBalances()
+
+    if (+negativeBalances > 1) {
+      errors.push(`Expected 1 wallet with a negative balance but found ${negativeBalances}`)
+    }
+
+    if (+negativeVoteBalances !== 0) {
+      errors.push(`Expected 0 wallets with a negative vote balance but found ${negativeVoteBalances}`)
+    }
 
     // Number of stored transactions equals the sum of block.numberOfTransactions in the database
     if (blockStats.numberOfTransactions !== transactionStats.count) {
@@ -665,33 +675,4 @@ module.exports = class PostgresConnection extends ConnectionInterface {
       }
     })
   }
-
-  /**
-   * This auxiliary method returns the number of blocks of the blockchain and
-   * is used to verify it
-   * @return {Number}
-   */
-  async __numberOfBlocks () {
-    const { count } = await this.db.blocks.count()
-
-    return count
-  }
-
-  /**
-   * This auxiliary method returns some stats about the blocks that are
-   * used to verify the blockchain
-   * @return {Promise}
-   */
-  async __blockStats () {
-    return this.db.blocks.statistics()
-  }
-
-  /**
-   * This auxiliary method returns some stats about the transactions that are
-   * used to verify the blockchain
-   * @return {Promise}
-   */
-  async __transactionStats () {
-    return this.db.transactions.statistics()
-  }
 }

packages/core-database-postgres/lib/queries/blocks/statistics.sql

@@ -1,4 +1,5 @@
 SELECT SUM ("number_of_transactions") AS "numberOfTransactions",
        SUM ("total_fee") AS "totalFee",
-       SUM ("total_amount") AS "totalAmount"
+       SUM ("total_amount") AS "totalAmount",
+       COUNT (DISTINCT "height") AS "count"
 FROM blocks

packages/core-database-postgres/lib/queries/index.js

@@ -44,6 +44,8 @@ module.exports = {
   },
   wallets: {
     all: loadQueryFile(__dirname, './wallets/all.sql'),
-    findByAddress: loadQueryFile(__dirname, './wallets/find-by-address.sql')
+    findByAddress: loadQueryFile(__dirname, './wallets/find-by-address.sql'),
+    findNegativeBalances: loadQueryFile(__dirname, './wallets/find-negative-balances.sql'),
+    findNegativeVoteBalances: loadQueryFile(__dirname, './wallets/find-negative-vote-balances.sql')
   }
 }

packages/core-database-postgres/lib/queries/wallets/find-negative-balances.sql

@@ -0,0 +1,3 @@
+SELECT COUNT (DISTINCT "address") AS "count"
+FROM wallets
+WHERE balance < 0;

packages/core-database-postgres/lib/queries/wallets/find-negative-vote-balances.sql

@@ -0,0 +1,3 @@
+SELECT COUNT (DISTINCT "address") AS "count"
+FROM wallets
+WHERE vote_balance < 0;

packages/core-database-postgres/lib/repositories/wallets.js

@@ -20,6 +20,22 @@ module.exports = class WalletsRepository extends Repository {
     return this.db.oneOrNone(sql.findByAddress, { address })
   }
 
+  /**
+   * Find all wallets that have a negative balance.
+   * @return {Promise}
+   */
+  async findNegativeBalances () {
+    return this.db.oneOrNone(sql.findNegativeBalances)
+  }
+
+  /**
+   * Find all wallets that have a negative vote balance.
+   * @return {Promise}
+   */
+  async findNegativeVoteBalances () {
+    return this.db.oneOrNone(sql.findNegativeVoteBalances)
+  }
+
   /**
    * Create or update a record matching the attributes, and fill it with values.
    * @param  {Object} wallet