Add getLoanScheme rpc (#638)

* Add new getloanscheme rpc

* Improve comment

* Improve code

* Minor

* Add correct error message

packages/jellyfish-api-core/__tests__/category/loan/getLoanScheme.test.ts

@@ -0,0 +1,42 @@
+import { LoanMasterNodeRegTestContainer } from './loan_container'
+import BigNumber from 'bignumber.js'
+import { Testing } from '@defichain/jellyfish-testing'
+
+describe('Loan getLoanScheme', () => {
+  const container = new LoanMasterNodeRegTestContainer()
+  const testing = Testing.create(container)
+
+  beforeAll(async () => {
+    await testing.container.start()
+    await testing.container.waitForWalletCoinbaseMaturity()
+  })
+
+  afterAll(async () => {
+    await testing.container.stop()
+  })
+
+  it('should getLoanScheme', async () => {
+    await testing.container.call('createloanscheme', [100, new BigNumber(1.5), 'scheme1'])
+    await testing.container.generate(1)
+
+    const data = await testing.rpc.loan.getLoanScheme('scheme1')
+    expect(data).toStrictEqual(
+      { id: 'scheme1', interestrate: new BigNumber(1.5), mincolratio: new BigNumber(100) }
+    )
+  })
+
+  it('should not getLoanScheme if id does not exist', async () => {
+    const promise = testing.rpc.loan.getLoanScheme('scheme2')
+    await expect(promise).rejects.toThrow('RpcApiError: \'Cannot find existing loan scheme with id scheme2\', code: -8, method: getloanscheme')
+  })
+
+  it('should not getLoanScheme if id is an empty string', async () => {
+    const promise = testing.rpc.loan.getLoanScheme('')
+    await expect(promise).rejects.toThrow('RpcApiError: \'id cannot be empty or more than 8 chars long\', code: -8, method: getloanscheme')
+  })
+
+  it('should not getLoanScheme if id is more than 8 characters', async () => {
+    const promise = testing.rpc.loan.getLoanScheme('x'.repeat(9))
+    await expect(promise).rejects.toThrow('RpcApiError: \'id cannot be empty or more than 8 chars long\', code: -8, method: getloanscheme')
+  })
+})

packages/jellyfish-api-core/src/category/loan.ts

@@ -68,6 +68,16 @@ export class Loan {
     return await this.client.call('listloanschemes', [], 'bignumber')
   }
 
+  /**
+   * Get loan scheme.
+   *
+   * @param {string} id Unique identifier of the loan scheme, max 8 chars.
+   * @return {Promise<GetLoanSchemeResult>}
+   */
+  async getLoanScheme (id: string): Promise<GetLoanSchemeResult> {
+    return await this.client.call('getloanscheme', [id], 'bignumber')
+  }
+
   /**
    * Sets the default loan scheme.
    *
@@ -151,6 +161,12 @@ export interface CollateralTokenDetail {
   activateAfterBlock: BigNumber
 }
 
+export interface GetLoanSchemeResult {
+  id: string
+  interestrate: BigNumber
+  mincolratio: BigNumber
+}
+
 export interface UTXO {
   txid: string
   vout: number

website/docs/jellyfish/api/loan.md

@@ -73,6 +73,22 @@ interface LoanSchemeResult {
 }
 ```
 
+## getLoanScheme
+
+Get loan scheme.
+
+```ts title="client.loan.getLoanScheme()"
+interface loan {
+  getLoanScheme (id: string): Promise<GetLoanSchemeResult>
+}
+
+interface GetLoanSchemeResult {
+  id: string
+  interestrate: BigNumber
+  mincolratio: BigNumber
+}
+```
+
 ## setDefaultLoanScheme
 
 Sets the default loan scheme.