btcd: add basic RPC tests using the rpctest package

This commit introduces a new file: rpcserver_test.go dedicated for
including integration tests for btcd using the new rpctest package.

The tests are created using a TestMain instance first creates a single
main harness which is intended to be re-used across tests instances.
Afterwards all registered RPC tests are executed, with proper clean up
being executed regardless of the passing state of the tests.

The following RPC calls are excessed by the initial set of tests added:
    * getbestblock
    * getblockcount
    * getblockhash

rpcserver_test.go

@@ -0,0 +1,133 @@
+// Copyright (c) 2016 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/rpctest"
+)
+
+func testGetBestBlock(r *rpctest.Harness, t *testing.T) {
+	_, prevbestHeight, err := r.Node.GetBestBlock()
+	if err != nil {
+		t.Fatalf("Call to `getbestblock` failed: %v", err)
+	}
+
+	// Create a new block connecting to the current tip.
+	generatedBlockHashes, err := r.Node.Generate(1)
+	if err != nil {
+		t.Fatalf("Unable to generate block: %v", err)
+	}
+
+	bestHash, bestHeight, err := r.Node.GetBestBlock()
+	if err != nil {
+		t.Fatalf("Call to `getbestblock` failed: %v", err)
+	}
+
+	// Hash should be the same as the newly submitted block.
+	if !bytes.Equal(bestHash[:], generatedBlockHashes[0][:]) {
+		t.Fatalf("Block hashes do not match. Returned hash %v, wanted "+
+			"hash %v", bestHash, generatedBlockHashes[0][:])
+	}
+
+	// Block height should now reflect newest height.
+	if bestHeight != prevbestHeight+1 {
+		t.Fatalf("Block heights do not match. Got %v, wanted %v",
+			bestHeight, prevbestHeight+1)
+	}
+}
+
+func testGetBlockCount(r *rpctest.Harness, t *testing.T) {
+	// Save the current count.
+	currentCount, err := r.Node.GetBlockCount()
+	if err != nil {
+		t.Fatalf("Unable to get block count: %v", err)
+	}
+
+	if _, err := r.Node.Generate(1); err != nil {
+		t.Fatalf("Unable to generate block: %v", err)
+	}
+
+	// Count should have increased by one.
+	newCount, err := r.Node.GetBlockCount()
+	if err != nil {
+		t.Fatalf("Unable to get block count: %v", err)
+	}
+	if newCount != currentCount+1 {
+		t.Fatalf("Block count incorrect. Got %v should be %v",
+			newCount, currentCount+1)
+	}
+}
+
+func testGetBlockHash(r *rpctest.Harness, t *testing.T) {
+	// Create a new block connecting to the current tip.
+	generatedBlockHashes, err := r.Node.Generate(1)
+	if err != nil {
+		t.Fatalf("Unable to generate block: %v", err)
+	}
+
+	info, err := r.Node.GetInfo()
+	if err != nil {
+		t.Fatalf("call to getinfo cailed: %v", err)
+	}
+
+	blockHash, err := r.Node.GetBlockHash(int64(info.Blocks))
+	if err != nil {
+		t.Fatalf("Call to `getblockhash` failed: %v", err)
+	}
+
+	// Block hashes should match newly created block.
+	if !bytes.Equal(generatedBlockHashes[0][:], blockHash[:]) {
+		t.Fatalf("Block hashes do not match. Returned hash %v, wanted "+
+			"hash %v", blockHash, generatedBlockHashes[0][:])
+	}
+}
+
+var rpcTestCases = []rpctest.HarnessTestCase{
+	testGetBestBlock,
+	testGetBlockCount,
+	testGetBlockHash,
+}
+
+var primaryHarness *rpctest.Harness
+
+func TestMain(m *testing.M) {
+	var err error
+	primaryHarness, err = rpctest.New(&chaincfg.SimNetParams, nil, nil)
+	if err != nil {
+		fmt.Println("unable to create primary harness: ", err)
+		os.Exit(1)
+	}
+
+	// Initialize the primary mining node with a chain of length 125,
+	// providing 25 mature coinbases to allow spending from for testing
+	// purposes.
+	if err = primaryHarness.SetUp(true, 25); err != nil {
+		fmt.Println("unable to setup test chain: ", err)
+		os.Exit(1)
+	}
+
+	exitCode := m.Run()
+
+	// Clean up the primary harness created above. This includes removing
+	// all temporary directories, and shutting down any created processes.
+	if err := primaryHarness.TearDown(); err != nil {
+		fmt.Println("unable to setup test chain: ", err)
+		os.Exit(1)
+	}
+
+	os.Exit(exitCode)
+}
+
+func TestRpcServer(t *testing.T) {
+	for _, testCase := range rpcTestCases {
+		testCase(primaryHarness, t)
+	}
+}