From e15d3008cfd59756db9570da9e47da6831313196 Mon Sep 17 00:00:00 2001
From: Dave Collins <dave@davec.name>
Date: Thu, 14 Apr 2016 00:19:23 -0500
Subject: [PATCH] mining: Improve tests for prio queue. (#667)

This improves the tests of the priority queue to include the secondary
sort ordering as well as adds some manual entries to ensure the edge
conditions are properly tested.

This also brings the priority queue test coverage up to 100%.
---
 mining_test.go | 121 +++++++++++++++++++++++++++++++++----------------
 1 file changed, 83 insertions(+), 38 deletions(-)

diff --git a/mining_test.go b/mining_test.go
index c7069637..e0b5bd72 100644
--- a/mining_test.go
+++ b/mining_test.go
@@ -15,51 +15,96 @@ import (
 // TestTxFeePrioHeap ensures the priority queue for transaction fees and
 // priorities works as expected.
 func TestTxFeePrioHeap(t *testing.T) {
-	// Create priority items with random fees and priorites.
-	const numItems = 1000
-	prioItems := make([]*txPrioItem, numItems)
-	highestFeePerKB := int64(0)
-	highestPrio := float64(0)
+	// Create some fake priority items that exercise the expected sort
+	// edge conditions.
+	testItems := []*txPrioItem{
+		{feePerKB: 5678, priority: 3},
+		{feePerKB: 5678, priority: 1},
+		{feePerKB: 5678, priority: 1}, // Duplicate fee and prio
+		{feePerKB: 5678, priority: 5},
+		{feePerKB: 5678, priority: 2},
+		{feePerKB: 1234, priority: 3},
+		{feePerKB: 1234, priority: 1},
+		{feePerKB: 1234, priority: 5},
+		{feePerKB: 1234, priority: 5}, // Duplicate fee and prio
+		{feePerKB: 1234, priority: 2},
+		{feePerKB: 10000, priority: 0}, // Higher fee, smaller prio
+		{feePerKB: 0, priority: 10000}, // Higher prio, lower fee
+	}
+
+	// Add random data in addition to the edge conditions already manually
+	// specified.
+	randSeed := rand.Int63()
+	defer func() {
+		if t.Failed() {
+			t.Logf("Random numbers using seed: %v", randSeed)
+		}
+	}()
+	prng := rand.New(rand.NewSource(randSeed))
 	for i := 0; i < 1000; i++ {
-		randPrio := rand.Float64() * 100
-		if randPrio > highestPrio {
-			highestPrio = randPrio
-		}
-		randFeePerKB := int64(rand.Float64() * btcutil.SatoshiPerBitcoin)
-		if randFeePerKB > highestFeePerKB {
-			highestFeePerKB = randFeePerKB
-		}
-		prioItems[i] = &txPrioItem{
-			tx:       nil,
-			priority: randPrio,
-			feePerKB: randFeePerKB,
-		}
+		testItems = append(testItems, &txPrioItem{
+			feePerKB: int64(prng.Float64() * btcutil.SatoshiPerBitcoin),
+			priority: prng.Float64() * 100,
+		})
 	}
 
-	// Test sorting by fee per KB.
-	priorityQueue := newTxPriorityQueue(numItems, true)
-	for i := 0; i < numItems; i++ {
-		heap.Push(priorityQueue, prioItems[i])
-	}
-	for i := 0; i < numItems; i++ {
-		prioItem := heap.Pop(priorityQueue).(*txPrioItem)
-		if prioItem.feePerKB > highestFeePerKB {
-			t.Fatalf("bad pop: %v fee per KB was more than last of %v",
-				prioItem.feePerKB, highestFeePerKB)
+	// Test sorting by fee per KB then priority.
+	var highest *txPrioItem
+	priorityQueue := newTxPriorityQueue(len(testItems), true)
+	for i := 0; i < len(testItems); i++ {
+		prioItem := testItems[i]
+		if highest == nil {
+			highest = prioItem
 		}
-		highestFeePerKB = prioItem.feePerKB
+		if prioItem.feePerKB >= highest.feePerKB &&
+			prioItem.priority > highest.priority {
+
+			highest = prioItem
+		}
+		heap.Push(priorityQueue, prioItem)
 	}
 
-	// Test sorting by priority.
-	priorityQueue = newTxPriorityQueue(numItems, false)
-	for i := 0; i < numItems; i++ {
-		heap.Push(priorityQueue, prioItems[i])
-	}
-	for i := 0; i < numItems; i++ {
+	for i := 0; i < len(testItems); i++ {
 		prioItem := heap.Pop(priorityQueue).(*txPrioItem)
-		if prioItem.priority > highestPrio {
-			t.Fatalf("bad pop: %v priority was more than last of %v",
-				prioItem.priority, highestPrio)
+		if prioItem.feePerKB >= highest.feePerKB &&
+			prioItem.priority > highest.priority {
+
+			t.Fatalf("fee sort: item (fee per KB: %v, "+
+				"priority: %v) higher than than prev "+
+				"(fee per KB: %v, priority %v)",
+				prioItem.feePerKB, prioItem.priority,
+				highest.feePerKB, highest.priority)
 		}
+		highest = prioItem
+	}
+
+	// Test sorting by priority then fee per KB.
+	highest = nil
+	priorityQueue = newTxPriorityQueue(len(testItems), false)
+	for i := 0; i < len(testItems); i++ {
+		prioItem := testItems[i]
+		if highest == nil {
+			highest = prioItem
+		}
+		if prioItem.priority >= highest.priority &&
+			prioItem.feePerKB > highest.feePerKB {
+
+			highest = prioItem
+		}
+		heap.Push(priorityQueue, prioItem)
+	}
+
+	for i := 0; i < len(testItems); i++ {
+		prioItem := heap.Pop(priorityQueue).(*txPrioItem)
+		if prioItem.priority >= highest.priority &&
+			prioItem.feePerKB > highest.feePerKB {
+
+			t.Fatalf("priority sort: item (fee per KB: %v, "+
+				"priority: %v) higher than than prev "+
+				"(fee per KB: %v, priority %v)",
+				prioItem.feePerKB, prioItem.priority,
+				highest.feePerKB, highest.priority)
+		}
+		highest = prioItem
 	}
 }