#11 Add getBalanceAsync in Erc20TokenService

src/factories/Erc20TokenTransactionBuilder.js

@@ -87,6 +87,25 @@ class Erc20TokenTransactionBuilder extends BaseTransactionBuilder {
     )
     return transactionDraft
   }
+
+  buildGetBalanceOfTransactionDraft(personalWalletAddress) {
+    this.constructor.checkEtherumAddress(personalWalletAddress)
+
+    const smartContractMethodName = 'balanceOf'
+    const smartContractParams = [personalWalletAddress]
+    const transactionParams = {
+      from: personalWalletAddress,
+      to: this.erc20TokenSmartContractAddress,
+    }
+
+    const transactionDraft = this.transactionLib.buildDraft(this.erc20TokenSmartContractInstance,
+      transactionParams, smartContractMethodName, smartContractParams)
+    this.log.debug(
+      { fn: 'buildGetBalanceOfTransactionDraft', personalWalletAddress },
+      'Erc20 token get balance of transaction draft builded successfully.',
+    )
+    return transactionDraft
+  }
 }
 
 module.exports = Erc20TokenTransactionBuilder

tests/unit/factories/Erc20TokenTransactionBuilder.test.js

@@ -128,4 +128,31 @@ describe('Erc20TokenTransactionBuilder', () => {
         }
       })
   })
+
+  describe('buildGetBalanceOfTransactionDraft', () => {
+    test('returns correct transaction object', () => {
+      const encodedDataForApproveMethod = '0x70a08231000000000000000000000000d57cb05ef66d2c7c952656ddf5096e02281e3d2e'
+
+      const expectedTransactionObjectDraft = MockTransactionDraftFactory
+        .build({ from: personalWalletAddress, data: encodedDataForApproveMethod, to: erc20TokenSmartContractAddress })
+
+      const result = erc20TokenTransactionBuilder.buildGetBalanceOfTransactionDraft(
+        personalWalletAddress,
+        tradingWalletSmartContractAddress,
+        quantity,
+      )
+
+      expect(result).toMatchObject(expectedTransactionObjectDraft)
+    })
+
+    const invalidPersonalWalletAddresses = [{}, [], 'I am not a valid ethereum address', 1, undefined, NaN, '0xNOOP']
+    test.each(invalidPersonalWalletAddresses)('raise InvalidEthereumAddress error if the personalWalletAddress is not a valid ethereum address %s',
+      (invalidPersonalWalletAddress) => {
+        try {
+          erc20TokenTransactionBuilder.buildGetBalanceOfTransactionDraft(invalidPersonalWalletAddress)
+        } catch (e) {
+          expect(e instanceof InvalidEthereumAddress).toBe(true)
+        }
+      })
+  })
 })

tests/unit/services/Erc20TokenService.test.js

@@ -72,29 +72,30 @@ describe('approveTrasferAsync', () => {
 
 describe('getAllowanceAsync', () => {
   const personalWalletAddress = '0x52daf0caee4cf4e66a9c90dad58c3f0cc4cbf785'
-  test('calls correctly ethapi sendRawTransaction correctly', async() => {
-    const expectedTransactionHash = '0xTransactionHash'
-    const nonceResponse = {
-      nonce: 4400,
-    }
-    const gasEstimationResponse = {
-      gas: 21000,
-      gasPrices: {
-        high: '0',
-        medium: '25395',
-        low: '0',
-      },
-    }
-    sandbox.stub(transactionLib, 'sign')
-    sandbox.stub(ethApiLib, 'sendRawTransactionAsync').returns({ hash: expectedTransactionHash })
-    sandbox.stub(ethApiLib, 'getAddressNonceAsync').returns(nonceResponse)
-    sandbox.stub(ethApiLib, 'getEstimateGasAsync').returns(gasEstimationResponse)
+  const tradingWalletAddress = '0x52daf0caee4cf4e66a9c90dad58c3f0cc4cbf585'
 
-    const transactionHash = await erc20TokenService.approveTrasferAsync(
+  test('calls correctly ethapi transactionCallAsync correctly', async() => {
+    const expectedAllowed = '10000000000000'
+
+    sandbox.stub(ethApiLib, 'transactionCallAsync').returns(expectedAllowed)
+
+    const result = await erc20TokenService.getAllowanceAsync(
       personalWalletAddress,
       tradingWalletAddress,
     )
+    expect(result).toEqual(expectedAllowed)
+  })
+})
 
-    expect(transactionHash).toEqual(expectedTransactionHash)
+describe('getBalanceOfAsync', () => {
+  const personalWalletAddress = '0x52daf0caee4cf4e66a9c90dad58c3f0cc4cbf785'
+
+  test('calls correctly ethapi transactionCallAsync correctly', async() => {
+    const expectedBalance = '10000000000000'
+
+    sandbox.stub(ethApiLib, 'transactionCallAsync').returns(expectedBalance)
+
+    const result = await erc20TokenService.getBalanceOfAsync(personalWalletAddress)
+    expect(result).toEqual(expectedBalance)
   })
 })