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arc_test.go
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arc_test.go
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// Copyright Chrono Technologies LLC
// SPDX-License-Identifier: MIT
package arc
import (
"bytes"
"crypto/sha256"
"encoding/binary"
"encoding/hex"
"errors"
"testing"
)
func TestLongestCommonPrefix(t *testing.T) {
tests := []struct {
a, b []byte
expected []byte
}{
// Basic cases.
{[]byte("apple"), []byte("app"), []byte("app")},
{[]byte("banana"), []byte("band"), []byte("ban")},
{[]byte("cat"), []byte("candy"), []byte("ca")},
{[]byte("no"), []byte("match"), nil},
{[]byte("fullmatch"), []byte("fullmatch"), []byte("fullmatch")},
// Edge cases.
{[]byte(""), []byte(""), nil},
{nil, nil, nil},
}
for _, test := range tests {
subject := longestCommonPrefix(test.a, test.b)
if !bytes.Equal(subject, test.expected) {
t.Errorf("unexpected prefix: got:%q, want:%q", subject, test.expected)
}
}
}
func TestSplitNode(t *testing.T) {
arc := &Arc{
root: &node{key: []byte("apple")},
numNodes: 1,
numRecords: 1,
}
// Test root split: "app" -> ["le", "store"]
{
newNode := &node{key: []byte("appstore")}
commonPrefix := longestCommonPrefix(arc.root.key, newNode.key)
arc.splitNode(nil, arc.root, newNode, commonPrefix)
// Root and its two children.
if arc.numNodes != 3 {
t.Errorf("unexpected node count: got:%d, want:3", arc.numNodes)
}
// "apple" and "appstore" records.
if arc.Len() != 2 {
t.Errorf("unexpected record count: got:%d, want:2", arc.numRecords)
}
if !bytes.Equal(arc.root.key, commonPrefix) {
t.Errorf("invalid root key: got:%q, want:%q", commonPrefix, arc.root.key)
}
expectedKeys := [][]byte{[]byte("le"), []byte("store")}
arc.root.forEachChild(func(i int, n *node) error {
if !bytes.Equal(n.key, expectedKeys[i]) {
t.Fatalf("unexpected key: got:%q, want:%q", n.key, expectedKeys[i])
}
if !n.isLeaf() {
t.Fatalf("expected %q to be a leaf node", n.key)
}
return nil
})
}
// Test non-root split using the "app" -> "store" node.
{
current, _ := arc.root.findChild([]byte("store"))
strawberryNode := &node{key: []byte("strawberry")}
commonPrefix := longestCommonPrefix(strawberryNode.key, current.key)
arc.splitNode(arc.root, current, strawberryNode, commonPrefix)
// "app" -> ["le", "st" -> ["ore", "rawberry"]]
if arc.numNodes != 5 {
t.Errorf("unexpected node count: got:%d, want:3", arc.numNodes)
}
// "apple", "appstore" and "strawberry" records.
if arc.Len() != 3 {
t.Errorf("unexpected record count: got:%d, want:2", arc.Len())
}
// "store" should now be further split to "st" -> "ore".
expectedKey := []byte("ore")
if !bytes.Equal(current.key, expectedKey) {
t.Errorf("unexpected key: got:%q, want:%q", current.key, expectedKey)
}
// "strawberry" should now be split to "st" -> "rawberry".
expectedKey = []byte("rawberry")
if !bytes.Equal(strawberryNode.key, expectedKey) {
t.Errorf("unexpected key: got:%q, want:%q", current.key, expectedKey)
}
}
}
func TestAdd(t *testing.T) {
testCases := []struct {
name string
key []byte
want error
}{
{name: "with nil key", key: nil, want: ErrNilKey},
{name: "with existing key", key: []byte("apricot"), want: ErrDuplicateKey},
{name: "with non-existing key", key: []byte("lychee"), want: nil},
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
arc := basicTestTree()
if err := arc.Add(tc.key, nil); err != tc.want {
t.Errorf("unexpected error: got:%v, want:%v", err, tc.want)
}
})
}
}
func TestPut(t *testing.T) {
testCases := []struct {
name string
records []testNode
expectedLevels [][]testNode
numNodes int
numRecords int
}{
{
name: "with no common prefix",
records: []testNode{
{key: []byte("apple"), value: []byte("1")},
{key: []byte("citron"), value: []byte("3")},
{key: []byte("durian"), value: []byte("4")},
{key: []byte("banana"), value: []byte("2")},
},
// Expected tree structure:
//
// .
// ├─ apple ("1")
// ├─ banana ("2")
// ├─ citron ("3")
// └─ durian ("4")
expectedLevels: [][]testNode{
{
{key: nil, isLeaf: false, isRecord: false, numChildren: 4},
},
{
{key: []byte("apple"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("banana"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("citron"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("durian"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 5,
numRecords: 4,
},
{
name: "with similar keys",
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("app"), value: []byte("6")},
{key: []byte("apple"), value: []byte("7")},
{key: []byte("approved"), value: []byte("12")},
{key: []byte("apply"), value: []byte("10")},
{key: []byte("apex"), value: []byte("4")},
{key: []byte("application"), value: []byte("9")},
{key: []byte("apology"), value: []byte("5")},
{key: []byte("appointment"), value: []byte("11")},
{key: []byte("appliance"), value: []byte("8")},
{key: []byte("ap"), value: []byte("3")},
{key: []byte("android"), value: []byte("2")},
},
// Expected tree structure:
//
// a ("1")
// ├─ ndroid ("2")
// └─ p ("3")
// ├─ ex ("4")
// ├─ ology ("5")
// └─ p ("6")
// ├─ l ("<nil>")
// │ ├─ e ("7")
// │ ├─ i ("<nil>")
// │ │ ├─ ance ("8")
// │ │ └─ cation ("9")
// │ └─ y ("10")
// ├─ ointment ("11")
// └─ roved ("12")
expectedLevels: [][]testNode{
{
{key: []byte("a"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("ndroid"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("p"), isLeaf: false, isRecord: true, numChildren: 3},
},
{
{key: []byte("ex"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("ology"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("p"), isLeaf: false, isRecord: true, numChildren: 3},
},
{
{key: []byte("l"), isLeaf: false, isRecord: false, numChildren: 3},
{key: []byte("ointment"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("roved"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("e"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("i"), isLeaf: false, isRecord: false, numChildren: 2},
{key: []byte("y"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("ance"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("cation"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 14,
numRecords: 12,
},
{
name: "with complex keys",
records: []testNode{
{key: []byte("ax"), value: []byte("1")},
{key: []byte("axb"), value: []byte("2")},
{key: []byte("axby"), value: []byte("3")},
{key: []byte("axbyz"), value: []byte("4")},
{key: []byte("axbyza"), value: []byte("5")},
{key: []byte("axbyzab"), value: []byte("6")},
{key: []byte("axy"), value: []byte("7")},
{key: []byte("axyb"), value: []byte("8")},
{key: []byte("axybz"), value: []byte("9")},
{key: []byte("axybza"), value: []byte("10")},
{key: []byte("axyz"), value: []byte("11")},
{key: []byte("axyza"), value: []byte("12")},
{key: []byte("axyzab"), value: []byte("13")},
{key: []byte("axyzb"), value: []byte("14")},
{key: []byte("axyzba"), value: []byte("15")},
},
// Expected tree structure:
//
// ax ("1")
// ├─ b ("2")
// │ └─ y ("3")
// │ └─ z ("4")
// │ └─ a ("5")
// │ └─ b ("6")
// └─ y ("7")
// ├─ b ("8")
// │ └─ z ("9")
// │ └─ a ("10")
// └─ z ("11")
// ├─ a ("12")
// │ └─ b ("13")
// └─ b ("14")
// └─ a ("15")
expectedLevels: [][]testNode{
{
{key: []byte("ax"), value: []byte("1"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("b"), value: []byte("2"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("y"), value: []byte("7"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("y"), value: []byte("3"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("b"), value: []byte("8"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("z"), value: []byte("11"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("z"), value: []byte("4"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("z"), value: []byte("9"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("a"), value: []byte("12"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("b"), value: []byte("14"), isLeaf: false, isRecord: true, numChildren: 1},
},
{
{key: []byte("a"), value: []byte("5"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("a"), value: []byte("10"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("b"), value: []byte("13"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("a"), value: []byte("15"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("b"), value: []byte("6"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 15,
numRecords: 15,
},
{
name: "with single byte prefix difference",
records: []testNode{
{key: []byte("35e2ac5f198beea10f1e8abf296b9bb9"), value: nil},
{key: []byte("35642e6d587bcdffeb28a33bd1cb6c73"), value: nil},
{key: []byte("e28a9e6d2f747e3a421646ca5c8f3c0b"), value: nil},
},
// Expected tree structure:
//
// .
// ├─ 35 ("<nil>")
// │ ├─ 642e6d587bcdffeb28a33bd1cb6c73 ("<nil>")
// │ └─ e2ac5f198beea10f1e8abf296b9bb9 ("<nil>")
// └─ e28a9e6d2f747e3a421646ca5c8f3c0b ("<nil>")
expectedLevels: [][]testNode{
{
{key: []byte(nil), isLeaf: false, isRecord: false, numChildren: 2},
},
{
{key: []byte("35"), isLeaf: false, isRecord: false, numChildren: 2},
{key: []byte("e28a9e6d2f747e3a421646ca5c8f3c0b"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("642e6d587bcdffeb28a33bd1cb6c73"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("e2ac5f198beea10f1e8abf296b9bb9"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 5,
numRecords: 3,
},
{
name: "with root expanding keys",
records: []testNode{
{key: []byte("apple"), value: nil},
{key: []byte("app"), value: nil},
},
expectedLevels: [][]testNode{
{
{key: []byte("app"), isLeaf: false, isRecord: true, numChildren: 1},
},
{
{key: []byte("le"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 2,
numRecords: 2,
},
{
name: "with parent expanding keys",
records: []testNode{
// Initial tree structure. The purpose of this test is to verify
// that the tree structure remains valid after expanding a parent
// node with multiple children.
//
// * ("1")
// ├─ aa ("2")
// │ ├─ x ("3")
// │ ├─ y ("4")
// │ └─ z ("5")
// ├─ bb ("6")
// └─ cc ("7")
{key: []byte("*"), value: []byte("1")},
{key: []byte("*aa"), value: []byte("2")},
{key: []byte("*aax"), value: []byte("3")},
{key: []byte("*aay"), value: []byte("4")},
{key: []byte("*aaz"), value: []byte("5")},
{key: []byte("*bb"), value: []byte("6")},
{key: []byte("*cc"), value: []byte("7")},
// Force key compression on "*" -> "aa" node by inserting a
// key that shares a shorter common prefix: "x" -> "a". The
// expected tree structure after the final insertion is:
//
// * ("1")
// ├─ a ("8")
// │ └─ a ("2")
// │ ├─ x ("3")
// │ ├─ y ("4")
// │ └─ z ("5")
// ├─ bb ("6")
// └─ cc ("7")
{key: []byte("*a"), value: []byte("8")},
},
expectedLevels: [][]testNode{
{
{key: []byte("*"), isLeaf: false, isRecord: true, numChildren: 3},
},
{
{key: []byte("a"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("bb"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("cc"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("a"), isLeaf: false, isRecord: true, numChildren: 3},
},
{
{key: []byte("x"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("y"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("z"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 8,
numRecords: 8,
},
{
name: "with identical blob values",
records: []testNode{
{key: []byte("x"), value: blobValueX()},
{key: []byte("y"), value: blobValueX()},
{key: []byte("z"), value: blobValueX()},
},
expectedLevels: [][]testNode{
{
{key: []byte(nil), isLeaf: false, isRecord: false, numChildren: 3},
},
{
{key: []byte("x"), value: blobValueX(), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("y"), value: blobValueX(), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("z"), value: blobValueX(), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 4,
numRecords: 3,
},
{
name: "with basic test nodes",
records: basicTestNodes(),
expectedLevels: basicTreeLevels(),
numNodes: basicTreeNumNodes(),
numRecords: len(basicTestNodes()),
},
{
name: "with ipv4 string keys",
records: ipStringTreeNodes(),
expectedLevels: ipStringTreeLevels(),
numNodes: ipStringTreeNumNodes(),
numRecords: len(ipStringTreeNodes()),
},
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
arc := New()
for _, record := range tc.records {
if err := arc.Put(record.key, record.value); err != nil {
t.Fatalf("unexpected error: %v", err)
}
}
if arc.numNodes != tc.numNodes {
t.Fatalf("unexpected numNodes, got:%d, want:%d", arc.numNodes, tc.numNodes)
}
if arc.numRecords != tc.numRecords {
t.Fatalf("unexpected numRecords, got:%d, want:%d", arc.numRecords, tc.numRecords)
}
nodesByLevel := collectNodesByLevel(arc.root)
if len(nodesByLevel) != len(tc.expectedLevels) {
t.Fatalf("unexpected tree depth: got:%d, want:%d", len(nodesByLevel), len(tc.expectedLevels))
}
for level, wantNodes := range tc.expectedLevels {
if len(wantNodes) != len(nodesByLevel[level]) {
t.Fatalf("invalid node count on level:%d, got:%d, want:%d", level, len(wantNodes), len(nodesByLevel[level]))
}
for i, want := range wantNodes {
got := nodesByLevel[level][i]
if !bytes.Equal(got.key, want.key) {
t.Fatalf("unexpected key: got:%q, want:%q", got.key, want.key)
}
if got.isLeaf() != want.isLeaf {
t.Fatalf("unexpected isLeaf: key:%q, got:%t, want:%t", got.key, got.isLeaf(), want.isLeaf)
}
if got.isRecord != want.isRecord {
t.Fatalf("unexpected isRecord: key:%q, got: %t, want:%t", got.key, got.isRecord, want.isRecord)
}
if got.numChildren != want.numChildren {
t.Fatalf("unexpected numChildren: key:%q, got:%d, want:%d", got.key, got.numChildren, want.numChildren)
}
}
}
// Test the record values.
for _, want := range tc.records {
if want.value != nil {
got, err := arc.Get(want.key)
if err != nil {
t.Fatalf("unexpected get error: %v", err)
}
if !bytes.Equal(got, want.value) {
t.Errorf("unexpected value: got:%q, want:%q", got, want.value)
}
}
}
})
}
}
func TestGet(t *testing.T) {
arc := basicTestTree()
// Test that all known keys are available.
for _, known := range basicTestTreeData() {
value, err := arc.Get(known.key)
if err != nil {
t.Errorf("unexpected error: %v", err)
}
if !bytes.Equal(value, known.data) {
t.Errorf("unexpected value: got:%q, want:%q", value, known.data)
}
}
// Test a key that do not exist.
if _, err := arc.Get([]byte("bogus")); err != ErrKeyNotFound {
t.Errorf("unexpected error: got:%v, want:%v", err, ErrKeyNotFound)
}
// Test nil key.
if _, err := arc.Get(nil); err != ErrNilKey {
t.Errorf("unexpected error: got:%v, want:%v", err, ErrNilKey)
}
}
func TestDelete(t *testing.T) {
testCases := []struct {
name string
deletionKeys [][]byte
records []testNode
expectedLevels [][]testNode
numNodes int
numRecords int
}{
{
name: "root:with no children",
deletionKeys: [][]byte{[]byte("a")},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
},
expectedLevels: [][]testNode{},
numNodes: 0,
numRecords: 0,
},
{
name: "root:with single leaf child",
deletionKeys: [][]byte{[]byte("a")},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("aa"), value: []byte("2")},
},
// Expected tree structure after deletion:
//
// aa ("2")
expectedLevels: [][]testNode{
{
{key: []byte("aa"), value: []byte("2"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 1,
numRecords: 1,
},
{
name: "root:with single non-leaf child",
deletionKeys: [][]byte{[]byte("a")},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("ab"), value: []byte("2")},
{key: []byte("abc"), value: []byte("3")},
},
// Expected tree structure after deletion:
//
//ab ("2")
//└─ c ("3")
expectedLevels: [][]testNode{
{
{key: []byte("ab"), value: []byte("2"), isLeaf: false, isRecord: true, numChildren: 1},
},
{
{key: []byte("c"), value: []byte("3"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 2,
numRecords: 2,
},
{
name: "root:with multiple children",
deletionKeys: [][]byte{[]byte("a")},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("ab"), value: []byte("2")},
{key: []byte("ac"), value: []byte("3")},
{key: []byte("ad"), value: []byte("4")},
},
// Expected tree structure after deletion. Structure remains the
// same, but the root node is no longer a record node:
//
// a ("<nil>")
// ├─ b ("2")
// ├─ c ("3")
// └─ d ("4")
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: nil, isLeaf: false, isRecord: false, numChildren: 3},
},
{
{key: []byte("b"), value: []byte("2"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("c"), value: []byte("3"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("d"), value: []byte("4"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 4,
numRecords: 3,
},
{
name: "root:node promotion",
deletionKeys: [][]byte{[]byte("a"), []byte("c"), []byte("d")},
// Test tree structure:
//
// .
// ├─ a ("1")
// ├─ b ("2")
// │ └─ x ("3")
// ├─ c ("4")
// └─ d ("5")
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("b"), value: []byte("2")},
{key: []byte("c"), value: []byte("4")},
{key: []byte("d"), value: []byte("5")},
{key: []byte("bx"), value: []byte("3")},
},
// Expected tree structure after deletion:
//
// b ("2")
// └─ x ("3")
expectedLevels: [][]testNode{
{
{key: []byte("b"), value: []byte("2"), isLeaf: false, isRecord: true, numChildren: 1},
},
{
{key: []byte("x"), value: []byte("3"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 2,
numRecords: 2,
},
{
name: "internal:single child node",
deletionKeys: [][]byte{[]byte("app")},
// Test tree structure:
//
// .
// ├─ ap ("1")
// │ └─ p ("2")
// │ └─ le ("3")
// │ └─ sauce ("4")
// └─ banana ("5")
records: []testNode{
{key: []byte("ap"), value: []byte("1")},
{key: []byte("app"), value: []byte("2")},
{key: []byte("apple"), value: []byte("3")},
{key: []byte("applesauce"), value: []byte("4")},
{key: []byte("banana"), value: []byte("5")},
},
// Expected tree structure after deletion:
// .
// ├─ ap ("1")
// │ └─ ple ("3")
// │ └─ sauce ("4")
// └─ banana ("5")
expectedLevels: [][]testNode{
{
{key: nil, value: nil, isLeaf: false, isRecord: false, numChildren: 2},
},
{
{key: []byte("ap"), value: []byte("1"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("banana"), value: []byte("5"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("ple"), value: []byte("3"), isLeaf: false, isRecord: true, numChildren: 1},
},
{
{key: []byte("sauce"), value: []byte("4"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 5,
numRecords: 4,
},
{
name: "internal:nodes with multiple children",
deletionKeys: [][]byte{
[]byte("app"), []byte("ap"),
},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("app"), value: []byte("6")},
{key: []byte("apple"), value: []byte("7")},
{key: []byte("approved"), value: []byte("12")},
{key: []byte("apply"), value: []byte("10")},
{key: []byte("apex"), value: []byte("4")},
{key: []byte("application"), value: []byte("9")},
{key: []byte("apology"), value: []byte("5")},
{key: []byte("appointment"), value: []byte("11")},
{key: []byte("appliance"), value: []byte("8")},
{key: []byte("ap"), value: []byte("3")},
{key: []byte("android"), value: []byte("2")},
},
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: []byte("1"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("ndroid"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("p"), isLeaf: false, isRecord: false, numChildren: 3},
},
{
{key: []byte("ex"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("ology"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("p"), isLeaf: false, isRecord: false, numChildren: 3},
},
{
{key: []byte("l"), isLeaf: false, isRecord: false, numChildren: 3},
{key: []byte("ointment"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("roved"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("e"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("i"), isLeaf: false, isRecord: false, numChildren: 2},
{key: []byte("y"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("ance"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("cation"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 14,
numRecords: 10,
},
{
name: "leaf:with single-child root parent",
deletionKeys: [][]byte{[]byte("aa")},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("aa"), value: []byte("2")},
},
// Expected tree structure after deletion:
//
// a ("1")
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: []byte("1"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 1,
numRecords: 1,
},
{
name: "leaf:with multi-child root parent",
deletionKeys: [][]byte{[]byte("ab")},
// Test tree structure:
//
// a ("1")
// ├─ a ("2")
// ├─ b ("3")
// └─ c ("4")
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("aa"), value: []byte("2")},
{key: []byte("ab"), value: []byte("3")},
{key: []byte("ac"), value: []byte("4")},
},
// Expected tree structure after deletion:
//
// a ("1")
// ├─ a ("2")
// └─ c ("4"
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: []byte("1"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("a"), value: []byte("2"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("c"), value: []byte("4"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 3,
numRecords: 3,
},
{
name: "leaf:from multi level tree",
deletionKeys: [][]byte{[]byte("aac"), []byte("aba")},
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("aa"), value: []byte("2")},
{key: []byte("aab"), value: []byte("3")},
{key: []byte("aac"), value: []byte("4")},
{key: []byte("ab"), value: []byte("5")},
{key: []byte("aba"), value: []byte("6")},
},
// Expected tree structure after deletion:
//
// a ("1")
// ├─ a ("2")
// │ └─ b ("3")
// └─ b ("5")
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: []byte("1"), isLeaf: false, isRecord: true, numChildren: 2},
},
{
{key: []byte("a"), value: []byte("2"), isLeaf: false, isRecord: true, numChildren: 1},
{key: []byte("b"), value: []byte("5"), isLeaf: true, isRecord: true, numChildren: 0},
},
{
{key: []byte("b"), value: []byte("3"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 4,
numRecords: 4,
},
{
name: "leaf:non-record parent with two children",
deletionKeys: [][]byte{[]byte("apple")},
// Test tree structure:
//
// a ("1")
// └─ p ("<nil>")
// ├─ ple ("2")
// └─ ricot ("3")
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("apple"), value: []byte("2")},
{key: []byte("apricot"), value: []byte("3")},
},
// Removal of the "ple" node has left the non-record parent: "p"
// with one child: "ricot". This means that the parent node is
// now reundant, and therefore the "p" and "ricot" nodes should
// be merged, forming a "pricot" node containing "ricot" data.
//
// Expected tree structure after deletion:
//
// a ("1")
// └─ pricot ("3")
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: []byte("1"), isLeaf: false, isRecord: true, numChildren: 1},
},
{
{key: []byte("pricot"), value: []byte("3"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 2,
numRecords: 2,
},
{
name: "leaf:all nodes",
deletionKeys: [][]byte{[]byte("aa"), []byte("ab"), []byte("ac")},
// Test tree structure:
//
// a ("1")
// ├─ a ("2")
// ├─ b ("3")
// └─ c ("4")
records: []testNode{
{key: []byte("a"), value: []byte("1")},
{key: []byte("aa"), value: []byte("2")},
{key: []byte("ab"), value: []byte("3")},
{key: []byte("ac"), value: []byte("4")},
},
// Expected tree structure after deletion:
//
// a ("1")
expectedLevels: [][]testNode{
{
{key: []byte("a"), value: []byte("1"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 1,
numRecords: 1,
},
{
name: "bottom up branch restructuring",
deletionKeys: [][]byte{[]byte("apple"), []byte("applet")},
// Test tree structure:
//
// ap ("<nil>")
// ├─ pl ("<nil>")
// │ ├─ e ("1")
// │ │ └─ t ("2")
// │ └─ ication ("3")
// └─ ricot ("4")
records: []testNode{
{key: []byte("apple"), value: []byte("1")},
{key: []byte("applet"), value: []byte("2")},
{key: []byte("application"), value: []byte("3")},
{key: []byte("apricot"), value: []byte("4")},
},
// Expected tree structure after deletion:
//
// ap ("<nil>")
// ├─ plication ("3")
// └─ ricot ("4")
expectedLevels: [][]testNode{
{
{key: []byte("ap"), value: nil, isLeaf: false, isRecord: false, numChildren: 2},
},
{
{key: []byte("plication"), value: []byte("3"), isLeaf: true, isRecord: true, numChildren: 0},
{key: []byte("ricot"), value: []byte("4"), isLeaf: true, isRecord: true, numChildren: 0},
},
},
numNodes: 3,
numRecords: 2,
},
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
arc := New()
for _, record := range tc.records {
if err := arc.Put(record.key, record.value); err != nil {
t.Fatalf("unexpected error: %v", err)
}
}
for _, deletionKey := range tc.deletionKeys {
if err := arc.Delete(deletionKey); err != nil {
t.Fatalf("unexpected deletion error: %v", err)
}
}
if arc.numNodes != tc.numNodes {
t.Fatalf("unexpected numNodes, got:%d, want:%d", arc.numNodes, tc.numNodes)
}
if arc.numRecords != tc.numRecords {
t.Fatalf("unexpected numRecords, got:%d, want:%d", arc.numRecords, tc.numRecords)
}
nodesByLevel := collectNodesByLevel(arc.root)
if len(nodesByLevel) != len(tc.expectedLevels) {
t.Fatalf("unexpected tree depth: got:%d, want:%d", len(nodesByLevel), len(tc.expectedLevels))
}
for level, wantNodes := range tc.expectedLevels {
if len(wantNodes) != len(nodesByLevel[level]) {
t.Fatalf("invalid node count on level:%d, got:%d, want:%d", level, len(wantNodes), len(nodesByLevel[level]))
}
for i, want := range wantNodes {
got := nodesByLevel[level][i]
if !bytes.Equal(got.key, want.key) {
t.Fatalf("unexpected key: got:%q, want:%q", got.key, want.key)
}
if got.isLeaf() != want.isLeaf {
t.Fatalf("unexpected isLeaf: got:%t, want:%t", got.isLeaf(), want.isLeaf)
}
if got.isRecord != want.isRecord {
t.Fatalf("unexpected isRecord: got: %t, want:%t", got.isRecord, want.isRecord)
}
if got.numChildren != want.numChildren {
t.Fatalf("unexpected numChildren: got:%d, want:%d", got.numChildren, want.numChildren)
}
}
}
// Ensure that all known keys are fetchable via the public API.
for _, record := range tc.records {
var expected error
var deletedKey bool
for _, deletionKey := range tc.deletionKeys {
if bytes.Equal(deletionKey, record.key) {
deletedKey = true
break
}
}
if deletedKey {