mining: Add basic priority calculation tests.

This adds some basic tests for the priority calculation code in the
mining policy.

mining/policy_test.go

@@ -0,0 +1,168 @@
+// 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 mining
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+)
+
+// newHashFromStr converts the passed big-endian hex string into a
+// chainhash.Hash.  It only differs from the one available in chainhash in that
+// it panics on an error since it will only (and must only) be called with
+// hard-coded, and therefore known good, hashes.
+func newHashFromStr(hexStr string) *chainhash.Hash {
+	hash, err := chainhash.NewHashFromStr(hexStr)
+	if err != nil {
+		panic("invalid hash in source file: " + hexStr)
+	}
+	return hash
+}
+
+// hexToBytes converts the passed hex string into bytes and will panic if there
+// is an error.  This is only provided for the hard-coded constants so errors in
+// the source code can be detected. It will only (and must only) be called with
+// hard-coded values.
+func hexToBytes(s string) []byte {
+	b, err := hex.DecodeString(s)
+	if err != nil {
+		panic("invalid hex in source file: " + s)
+	}
+	return b
+}
+
+// newUtxoViewpoint returns a new utxo view populated with outputs of the
+// provided source transactions as if there were available at the respective
+// block height specified in the heights slice.  The length of the source txns
+// and source tx heights must match or it will panic.
+func newUtxoViewpoint(sourceTxns []*wire.MsgTx, sourceTxHeights []int32) *blockchain.UtxoViewpoint {
+	if len(sourceTxns) != len(sourceTxHeights) {
+		panic("each transaction must have its block height specified")
+	}
+
+	view := blockchain.NewUtxoViewpoint()
+	for i, tx := range sourceTxns {
+		view.AddTxOuts(btcutil.NewTx(tx), sourceTxHeights[i])
+	}
+	return view
+}
+
+// TestCalcPriority ensures the priority calculations work as intended.
+func TestCalcPriority(t *testing.T) {
+	// commonSourceTx1 is a valid transaction used in the tests below as an
+	// input to transactions that are having their priority calculated.
+	//
+	// From block 7 in main blockchain.
+	// tx 0437cd7f8525ceed2324359c2d0ba26006d92d856a9c20fa0241106ee5a597c9
+	commonSourceTx1 := &wire.MsgTx{
+		Version: 1,
+		TxIn: []*wire.TxIn{{
+			PreviousOutPoint: wire.OutPoint{
+				Hash:  chainhash.Hash{},
+				Index: wire.MaxPrevOutIndex,
+			},
+			SignatureScript: hexToBytes("04ffff001d0134"),
+			Sequence:        0xffffffff,
+		}},
+		TxOut: []*wire.TxOut{{
+			Value: 5000000000,
+			PkScript: hexToBytes("410411db93e1dcdb8a016b49840f8c5" +
+				"3bc1eb68a382e97b1482ecad7b148a6909a5cb2e0ead" +
+				"dfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8" +
+				"643f656b412a3ac"),
+		}},
+		LockTime: 0,
+	}
+
+	// commonRedeemTx1 is a valid transaction used in the tests below as the
+	// transaction to calculate the priority for.
+	//
+	// It originally came from block 170 in main blockchain.
+	commonRedeemTx1 := &wire.MsgTx{
+		Version: 1,
+		TxIn: []*wire.TxIn{{
+			PreviousOutPoint: wire.OutPoint{
+				Hash: *newHashFromStr("0437cd7f8525ceed232435" +
+					"9c2d0ba26006d92d856a9c20fa0241106ee5" +
+					"a597c9"),
+				Index: 0,
+			},
+			SignatureScript: hexToBytes("47304402204e45e16932b8af" +
+				"514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5f" +
+				"b8cd410220181522ec8eca07de4860a4acdd12909d83" +
+				"1cc56cbbac4622082221a8768d1d0901"),
+			Sequence: 0xffffffff,
+		}},
+		TxOut: []*wire.TxOut{{
+			Value: 1000000000,
+			PkScript: hexToBytes("4104ae1a62fe09c5f51b13905f07f06" +
+				"b99a2f7159b2225f374cd378d71302fa28414e7aab37" +
+				"397f554a7df5f142c21c1b7303b8a0626f1baded5c72" +
+				"a704f7e6cd84cac"),
+		}, {
+			Value: 4000000000,
+			PkScript: hexToBytes("410411db93e1dcdb8a016b49840f8c5" +
+				"3bc1eb68a382e97b1482ecad7b148a6909a5cb2e0ead" +
+				"dfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8" +
+				"643f656b412a3ac"),
+		}},
+		LockTime: 0,
+	}
+
+	tests := []struct {
+		name       string                    // test description
+		tx         *wire.MsgTx               // tx to calc priority for
+		utxoView   *blockchain.UtxoViewpoint // inputs to tx
+		nextHeight int32                     // height for priority calc
+		want       float64                   // expected priority
+	}{
+		{
+			name: "one height 7 input, prio tx height 169",
+			tx:   commonRedeemTx1,
+			utxoView: newUtxoViewpoint([]*wire.MsgTx{commonSourceTx1},
+				[]int32{7}),
+			nextHeight: 169,
+			want:       5e9,
+		},
+		{
+			name: "one height 100 input, prio tx height 169",
+			tx:   commonRedeemTx1,
+			utxoView: newUtxoViewpoint([]*wire.MsgTx{commonSourceTx1},
+				[]int32{100}),
+			nextHeight: 169,
+			want:       2129629629.6296296,
+		},
+		{
+			name: "one height 7 input, prio tx height 100000",
+			tx:   commonRedeemTx1,
+			utxoView: newUtxoViewpoint([]*wire.MsgTx{commonSourceTx1},
+				[]int32{7}),
+			nextHeight: 100000,
+			want:       3086203703703.7036,
+		},
+		{
+			name: "one height 100 input, prio tx height 100000",
+			tx:   commonRedeemTx1,
+			utxoView: newUtxoViewpoint([]*wire.MsgTx{commonSourceTx1},
+				[]int32{100}),
+			nextHeight: 100000,
+			want:       3083333333333.3335,
+		},
+	}
+
+	for i, test := range tests {
+		got := CalcPriority(test.tx, test.utxoView, test.nextHeight)
+		if got != test.want {
+			t.Errorf("CalcPriority #%d (%q): unexpected priority "+
+				"got %v want %v", i, test.name, got, test.want)
+			continue
+		}
+	}
+}