File size: 4,910 Bytes
6380833 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 | package treex
import (
"errors"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
type testVal struct{ id int }
func TestNewTree_NilRoot(t *testing.T) {
tr, err := NewTree[*testVal](nil)
require.Error(t, err)
assert.Nil(t, tr)
assert.ErrorIs(t, err, ErrRootNodeIsNil)
}
func TestNewTree_MutatesInput(t *testing.T) {
// Graph:
// 1
// └── 2
v := &testVal{id: 1}
root := NewNode(v)
childVal := &testVal{id: 2}
child := NewNode(childVal)
root.AddChild(child)
origParent := child.Parent()
origChildren := root.Children()
tr, err := NewTree(root)
require.NoError(t, err)
require.NotNil(t, tr)
// original nodes remain unchanged as we didn't mutat them
assert.Equal(t, origParent, child.Parent())
assert.Equal(t, origChildren, root.Children())
assert.NotNil(t, tr.root)
// ensure root pointer is the same (can be mutated)
assert.Same(t, root, tr.root)
}
func TestNewTree_DontChangeRoot(t *testing.T) {
// Graph:
// 1
// └── 2
// └── 3
v1 := &testVal{id: 1}
v2 := &testVal{id: 2}
v3 := &testVal{id: 3}
grand := NewNode(v1)
parent := NewNode(v2)
child := NewNode(v3)
grand.AddChild(parent)
parent.AddChild(child)
// Build tree starting from parent (non-root)
tr, err := NewTree(parent)
require.NoError(t, err)
require.NotNil(t, tr)
// It should expose the same children as the provided parent
require.Len(t, tr.root.Children(), 1)
assert.Equal(t, child, tr.root.Children()[0])
// Provided parent remains with its original parent
assert.Equal(t, grand, parent.Parent())
// Pointer identity is the same
assert.Same(t, parent, tr.root)
}
func TestNewTree_AcyclicValid(t *testing.T) {
// Graph:
// 1
// ├── 2
// └── 3
v1 := &testVal{id: 1}
v2 := &testVal{id: 2}
v3 := &testVal{id: 3}
r := NewNode(v1)
c1 := NewNode(v2)
c2 := NewNode(v3)
r.AddChild(c1)
r.AddChild(c2)
tr, err := NewTree(r)
require.NoError(t, err)
require.NotNil(t, tr)
}
func TestNewTree_DetectsCycle(t *testing.T) {
// Graph (cycle):
// 1 -> 2 -> 1
v1 := &testVal{id: 1}
v2 := &testVal{id: 2}
n1 := NewNode(v1)
n2 := NewNode(v2)
n1.AddChild(n2)
// introduce a cycle by making n2 a parent of n1
n2.AddChild(n1)
tr, err := NewTree(n1)
require.Error(t, err)
assert.Nil(t, tr)
assert.ErrorIs(t, err, ErrGraphHasCycle)
}
func TestNewTree_InvalidGraph_NilChild(t *testing.T) {
// Graph (invalid):
// 1
// └── <nil>
v1 := &testVal{id: 1}
r := NewNode(v1)
// Corrupt structure: append a nil child directly
r.children = append(r.children, nil)
tr, err := NewTree(r)
require.Error(t, err)
assert.Nil(t, tr)
assert.ErrorIs(t, err, ErrNodeGraphInvalid)
}
func TestDFS_PreOrderTraversal(t *testing.T) {
// Graph:
// 1
// ├── 2
// │ └── 4
// └── 3
v1 := &testVal{id: 1}
v2 := &testVal{id: 2}
v3 := &testVal{id: 3}
v4 := &testVal{id: 4}
r := NewNode(v1)
c1 := NewNode(v2)
c2 := NewNode(v3)
c1a := NewNode(v4)
r.AddChild(c1)
r.AddChild(c2)
c1.AddChild(c1a)
trr, err := NewTree(r)
require.NoError(t, err)
var visited []int
err = trr.DFS(func(n *Node[*testVal]) (bool, error) {
visited = append(visited, n.Value().id)
return false, nil
})
require.NoError(t, err)
assert.Equal(t, []int{1, 2, 4, 3}, visited, "preorder traversal expected")
}
func TestDFS_PruneSubtreeOnStop(t *testing.T) {
// Graph:
// 1
// ├── 2
// │ └── 4
// └── 3
v1 := &testVal{id: 1}
v2 := &testVal{id: 2}
v3 := &testVal{id: 3}
v4 := &testVal{id: 4}
r := NewNode(v1)
c1 := NewNode(v2)
c2 := NewNode(v3)
c1a := NewNode(v4)
r.AddChild(c1)
r.AddChild(c2)
c1.AddChild(c1a)
trr, err := NewTree(r)
require.NoError(t, err)
var visited []int
err = trr.DFS(func(n *Node[*testVal]) (bool, error) {
visited = append(visited, n.Value().id)
if n.Value().id == 2 {
return true, nil // prune children of 2 (i.e., node 4)
}
return false, nil
})
require.NoError(t, err)
assert.Equal(t, []int{1, 2, 3}, visited, "should prune 2's subtree and continue with siblings")
}
func TestDFS_ErrorPropagation(t *testing.T) {
// Graph:
// 1
// ├── 2
// │ └── 4
// └── 3
// └── 5
v1 := &testVal{id: 1}
v2 := &testVal{id: 2}
v3 := &testVal{id: 3}
v4 := &testVal{id: 4}
v5 := &testVal{id: 5}
r := NewNode(v1)
c1 := NewNode(v2)
c2 := NewNode(v3)
c1a := NewNode(v4)
c2a := NewNode(v5)
r.AddChild(c1)
r.AddChild(c2)
c1.AddChild(c1a)
c2.AddChild(c2a)
trr, err := NewTree(r)
require.NoError(t, err)
var visited []int
boom := errors.New("boom")
err = trr.DFS(func(n *Node[*testVal]) (bool, error) {
visited = append(visited, n.Value().id)
if n.Value().id == 3 {
return false, boom
}
return false, nil
})
require.Error(t, err)
assert.ErrorIs(t, err, boom)
// Should not have visited 5 (child of 3) after error
assert.Equal(t, []int{1, 2, 4, 3}, visited)
}
|