Add remove ocean liquidity function (#685)

Add remove ocean liquidity function

Signed-off-by: mihaisc <mihai.scarlat@smartcontrol.ro>

src/balancer/OceanPool.ts

@@ -749,6 +749,7 @@ export class OceanPool extends Pool {
    * @param {String} account
    * @param {String} poolAddress
    * @param {String} amount datatoken amount
+   * @param {String} maximumPoolShares
    * @return {TransactionReceipt}
    */
   public async removeDTLiquidity(
@@ -828,10 +829,44 @@ export class OceanPool extends Pool {
   }
 
   /**
-   * Remove Ocean Token amount from pool liquidity
+   * Remove Ocean Token amount from pool liquidity based on the minimum allowed of Ocean Tokens received
+   * @param {String} account
+   * @param {String} poolAddress
+   * @param {String} poolShares pool shares
+   * @param {String} minOcean minimum amount of OCEAN received
+   * @return {TransactionReceipt}
+   */
+  public async removeOceanLiquidityWithMinimum(
+    account: string,
+    poolAddress: string,
+    poolShares: string,
+    minOcean: string
+  ): Promise<TransactionReceipt> {
+    if (this.oceanAddress == null) {
+      this.logger.error('ERROR: oceanAddress is not defined')
+      return null
+    }
+    const usershares = await this.sharesBalance(account, poolAddress)
+    if (parseFloat(usershares) < parseFloat(poolShares)) {
+      this.logger.error('ERROR: Not enough poolShares')
+      return null
+    }
+
+    return super.exitswapPoolAmountIn(
+      account,
+      poolAddress,
+      this.oceanAddress,
+      poolShares,
+      minOcean
+    )
+  }
+
+  /**
+   * Remove Ocean Token amount from pool liquidity based on the maximum pool shares allowed to be spent
    * @param {String} account
    * @param {String} poolAddress
    * @param {String} amount Ocean Token amount in OCEAN
+   * @param {String} maximumPoolShares maximum pool shares allowed to be spent
    * @return {TransactionReceipt}
    */
   public async removeOceanLiquidity(

test/unit/balancer/Balancer.test.ts

@@ -34,7 +34,7 @@ describe('Balancer flow', () => {
   let contracts: TestContractHandler
   let datatoken: DataTokens
   let tokenAddress: string
-  let consoleDebug: true
+  const consoleDebug = false
   let greatPool: string
   const tokenAmount = '1000'
   const transferAmount = '200'
@@ -405,6 +405,7 @@ describe('Balancer flow', () => {
     if (consoleDebug) console.log('poolShares:' + poolShares)
     assert(parseFloat(poolShares) > 0)
   })
+
   it('Bob should remove Ocean liquidity from pool ', async () => {
     const currentDtReserve = await Pool.getOceanReserve(greatPool)
     const bobDtBalance = await datatoken.balance(oceanTokenAddress, bob)
@@ -427,6 +428,42 @@ describe('Balancer flow', () => {
     assert(parseFloat(bobDtBalance) < parseFloat(newbobDtBalance))
     assert(parseFloat(poolShares) > parseFloat(newpoolShares))
   })
+
+  it('Bob should remove Ocean liquidity from pool by specifying slippage ', async () => {
+    const currentDtReserve = await Pool.getOceanReserve(greatPool)
+    const bobDtBalance = await datatoken.balance(oceanTokenAddress, bob)
+
+    const poolShares = await Pool.sharesBalance(bob, greatPool)
+    const poolSharesAmount = '0.75'
+
+    if (consoleDebug) console.log('currentDtReserve:' + currentDtReserve)
+    if (consoleDebug) console.log('bobDtBalance:' + bobDtBalance)
+    if (consoleDebug) console.log('poolShares:' + poolShares)
+
+    const oceanAmount = await Pool.getOceanRemovedforPoolShares(
+      greatPool,
+      poolSharesAmount
+    )
+    // 10% slippage
+    const oceanAmountWithSlippage = parseFloat(oceanAmount) * 0.9
+    await Pool.removeOceanLiquidityWithMinimum(
+      bob,
+      greatPool,
+      poolSharesAmount,
+      oceanAmountWithSlippage.toString()
+    )
+
+    const newDtReserve = await Pool.getOceanReserve(greatPool)
+    const newbobDtBalance = await datatoken.balance(oceanTokenAddress, bob)
+    const newpoolShares = await Pool.sharesBalance(bob, greatPool)
+
+    if (consoleDebug) console.log('newDtReserve:' + newDtReserve)
+    if (consoleDebug) console.log('newbobDtBalance:' + newbobDtBalance)
+    if (consoleDebug) console.log('newpoolShares:' + newpoolShares)
+    assert(parseFloat(newDtReserve) < parseFloat(currentDtReserve))
+    assert(parseFloat(bobDtBalance) < parseFloat(newbobDtBalance))
+    assert(parseFloat(poolShares) > parseFloat(newpoolShares))
+  })
   it('Alice should know how many tokens she will get for removing all liquidity', async () => {
     const aliceShares = await Pool.sharesBalance(alice, greatPool)
     const amounts = await Pool.getTokensRemovedforPoolShares(greatPool, aliceShares)