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142f1a8c6b
This is a change in design for the graph.NodesOf family of functions. The alternative was to provide an equivalent set of non-panicking routines in graph for internal use. The protection that was intended with the panic was to panic early rather than late when an indeterminate iterator exhausts slice index space. I think in hindsight this was an error and we should let things blow up in that (likely rare) situation. The majority of changes are in test code. Outside the iterator package, which is intimately tied to the determined iterator implementations, only one test now fails if an indeterminate iterator is used, product's Modular extended sub-graph isomorphism example, which is an algorithm that would have time complexity issues with large iterators anyway.
94 lines
2.4 KiB
Go
94 lines
2.4 KiB
Go
// Copyright ©2019 The Gonum Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package graph_test
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import (
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"fmt"
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"testing"
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"golang.org/x/exp/rand"
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"gonum.org/v1/gonum/graph"
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"gonum.org/v1/gonum/graph/graphs/gen"
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"gonum.org/v1/gonum/graph/iterator"
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"gonum.org/v1/gonum/graph/simple"
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)
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var complementTests = []struct {
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g graph.Graph
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}{
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{g: gnp(100, 0, rand.NewSource(1))},
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{g: gnp(100, 0.05, rand.NewSource(1))},
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{g: gnp(100, 0.5, rand.NewSource(1))},
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{g: gnp(100, 0.95, rand.NewSource(1))},
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{g: gnp(100, 1, rand.NewSource(1))},
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}
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func TestComplement(t *testing.T) {
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for _, test := range complementTests {
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n := len(graph.NodesOf(test.g.Nodes()))
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wantM := n * (n - 1) // Double counting edges, but no self-loops.
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var gotM int
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iter := test.g.Nodes()
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for iter.Next() {
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id := iter.Node().ID()
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to := test.g.From(id)
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for to.Next() {
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gotM++
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}
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toC := graph.Complement{test.g}.From(id)
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for toC.Next() {
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gotM++
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}
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}
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if gotM != wantM {
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t.Errorf("unexpected number of edges in sum of input and complement: got:%d want:%d", gotM, wantM)
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}
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}
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}
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func gnp(n int, p float64, src rand.Source) *simple.UndirectedGraph {
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g := simple.NewUndirectedGraph()
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err := gen.Gnp(g, n, p, src)
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if err != nil {
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panic(fmt.Sprintf("gnp: bad test: %v", err))
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}
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return g
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}
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var nodeFilterIteratorTests = []struct {
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src, filter graph.Nodes
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root int64
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len int
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}{
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{src: iterator.NewOrderedNodes([]graph.Node{simple.Node(0)}), filter: graph.Empty, root: 0, len: 0},
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{src: iterator.NewOrderedNodes([]graph.Node{simple.Node(0), simple.Node(1)}), filter: graph.Empty, root: 0, len: 1},
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{src: iterator.NewOrderedNodes([]graph.Node{simple.Node(0), simple.Node(1), simple.Node(2)}), filter: iterator.NewOrderedNodes([]graph.Node{simple.Node(1)}), root: 0, len: 1},
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}
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func TestNodeFilterIterator(t *testing.T) {
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for _, test := range nodeFilterIteratorTests {
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it := graph.NewNodeFilterIterator(test.src, test.filter, test.root)
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if it.Len() < 0 {
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t.Logf("don't test indeterminate iterators: %T", it)
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continue
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}
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for i := 0; i < 2; i++ {
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n := it.Len()
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if n != test.len {
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t.Errorf("unexpected length of iterator construction/reset: got:%d want:%d", n, test.len)
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}
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for it.Next() {
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n--
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}
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if n != 0 {
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t.Errorf("unexpected remaining nodes after iterator completion: got:%d want:0", n)
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}
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it.Reset()
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}
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}
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}
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