fix: add tx instruction->transfer data functionality

web3.js/test/system-program.test.js

@@ -1,6 +1,12 @@
 // @flow
 
-import {Account, BudgetProgram, SystemProgram} from '../src';
+import {
+  Account,
+  BudgetProgram,
+  SystemInstruction,
+  SystemProgram,
+  Transaction,
+} from '../src';
 
 test('createAccount', () => {
   const from = new Account();
@@ -43,3 +49,95 @@ test('assign', () => {
   expect(transaction.programId).toEqual(SystemProgram.programId);
   // TODO: Validate transaction contents more
 });
+
+test('SystemInstruction create', () => {
+  const from = new Account();
+  const to = new Account();
+  const program = new Account();
+  const amount = 42;
+  const space = 100;
+  const recentBlockhash = 'EETubP5AKHgjPAhzPAFcb8BAY1hMH639CWCFTqi3hq1k'; // Arbitrary known recentBlockhash
+  const create = SystemProgram.createAccount(
+    from.publicKey,
+    to.publicKey,
+    amount,
+    space,
+    program.publicKey,
+  );
+  const transaction = new Transaction({recentBlockhash}).add(create);
+
+  const systemInstruction = SystemInstruction.from(transaction.instructions[0]);
+  expect(systemInstruction.From).toEqual(from.publicKey);
+  expect(systemInstruction.To).toEqual(to.publicKey);
+  expect(systemInstruction.Amount).toEqual(amount);
+  expect(systemInstruction.programId).toEqual(SystemProgram.programId);
+});
+
+test('SystemInstruction transfer', () => {
+  const from = new Account();
+  const to = new Account();
+  const amount = 42;
+  const recentBlockhash = 'EETubP5AKHgjPAhzPAFcb8BAY1hMH639CWCFTqi3hq1k'; // Arbitrary known recentBlockhash
+  const transfer = SystemProgram.transfer(from.publicKey, to.publicKey, amount);
+  const transaction = new Transaction({recentBlockhash}).add(transfer);
+  transaction.sign(from);
+
+  const systemInstruction = SystemInstruction.from(transaction.instructions[0]);
+  expect(systemInstruction.From).toEqual(from.publicKey);
+  expect(systemInstruction.To).toEqual(to.publicKey);
+  expect(systemInstruction.Amount).toEqual(amount);
+  expect(systemInstruction.programId).toEqual(SystemProgram.programId);
+});
+
+test('SystemInstruction assign', () => {
+  const from = new Account();
+  const program = new Account();
+  const recentBlockhash = 'EETubP5AKHgjPAhzPAFcb8BAY1hMH639CWCFTqi3hq1k'; // Arbitrary known recentBlockhash
+  const assign = SystemProgram.assign(from.publicKey, program.publicKey);
+  const transaction = new Transaction({recentBlockhash}).add(assign);
+  transaction.sign(from);
+
+  const systemInstruction = SystemInstruction.from(transaction.instructions[0]);
+  expect(systemInstruction.From).toBeNull();
+  expect(systemInstruction.To).toBeNull();
+  expect(systemInstruction.Amount).toBeNull();
+  expect(systemInstruction.programId).toEqual(SystemProgram.programId);
+});
+
+test('non-SystemInstruction error', () => {
+  const from = new Account();
+  const program = new Account();
+  const to = new Account();
+
+  const badProgramId = {
+    keys: [
+      {pubkey: from.publicKey, isSigner: true, isDebitable: true},
+      {pubkey: to.publicKey, isSigner: false, isDebitable: false},
+    ],
+    programId: BudgetProgram.programId,
+    data: Buffer.from([2, 0, 0, 0]),
+  };
+  expect(() => {
+    new SystemInstruction(badProgramId);
+  }).toThrow();
+
+  const amount = 123;
+  const recentBlockhash = 'EETubP5AKHgjPAhzPAFcb8BAY1hMH639CWCFTqi3hq1k'; // Arbitrary known recentBlockhash
+  const budgetPay = BudgetProgram.pay(
+    from.publicKey,
+    program.publicKey,
+    to.publicKey,
+    amount,
+  );
+  const transaction = new Transaction({recentBlockhash}).add(budgetPay);
+  transaction.sign(from);
+
+  expect(() => {
+    SystemInstruction.from(transaction.instructions[1]);
+  }).toThrow();
+
+  transaction.instructions[0].data[0] = 4;
+  expect(() => {
+    SystemInstruction.from(transaction.instructions[0]);
+  }).toThrow();
+});