xref: /llvm-project/llvm/unittests/ADT/BreadthFirstIteratorTest.cpp (revision 797330e96c5abf0f1c623c1eb5ca69de28b484be)
1 //=== llvm/unittest/ADT/BreadthFirstIteratorTest.cpp - BFS iterator tests -===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/ADT/BreadthFirstIterator.h"
10 #include "TestGraph.h"
11 #include "gtest/gtest.h"
12 
13 #include <array>
14 #include <iterator>
15 #include <type_traits>
16 
17 #include <cstddef>
18 
19 using namespace llvm;
20 
21 namespace llvm {
22 
23 TEST(BreadthFristIteratorTest, Basic) {
24   typedef bf_iterator<Graph<4>> BFIter;
25 
26   Graph<4> G;
27   G.AddEdge(0, 1);
28   G.AddEdge(0, 2);
29   G.AddEdge(1, 3);
30 
31   auto It = BFIter::begin(G);
32   auto End = BFIter::end(G);
33   EXPECT_EQ(It.getLevel(), 0U);
34   EXPECT_EQ(*It, G.AccessNode(0));
35   ++It;
36   EXPECT_EQ(It.getLevel(), 1U);
37   EXPECT_EQ(*It, G.AccessNode(1));
38   ++It;
39   EXPECT_EQ(It.getLevel(), 1U);
40   EXPECT_EQ(*It, G.AccessNode(2));
41   ++It;
42   EXPECT_EQ(It.getLevel(), 2U);
43   EXPECT_EQ(*It, G.AccessNode(3));
44   ++It;
45   EXPECT_EQ(It, End);
46 }
47 
48 TEST(BreadthFristIteratorTest, Cycle) {
49   typedef bf_iterator<Graph<4>> BFIter;
50 
51   Graph<4> G;
52   G.AddEdge(0, 1);
53   G.AddEdge(1, 0);
54   G.AddEdge(1, 2);
55   G.AddEdge(2, 1);
56   G.AddEdge(2, 1);
57   G.AddEdge(2, 3);
58   G.AddEdge(3, 2);
59   G.AddEdge(3, 1);
60   G.AddEdge(3, 0);
61 
62   auto It = BFIter::begin(G);
63   auto End = BFIter::end(G);
64   EXPECT_EQ(It.getLevel(), 0U);
65   EXPECT_EQ(*It, G.AccessNode(0));
66   ++It;
67   EXPECT_EQ(It.getLevel(), 1U);
68   EXPECT_EQ(*It, G.AccessNode(1));
69   ++It;
70   EXPECT_EQ(It.getLevel(), 2U);
71   EXPECT_EQ(*It, G.AccessNode(2));
72   ++It;
73   EXPECT_EQ(It.getLevel(), 3U);
74   EXPECT_EQ(*It, G.AccessNode(3));
75   ++It;
76   EXPECT_EQ(It, End);
77 }
78 
79 static_assert(
80     std::is_convertible_v<decltype(*std::declval<bf_iterator<Graph<3>>>()),
81                           typename bf_iterator<Graph<3>>::reference>);
82 
83 // bf_iterator should be (at-least) a forward-iterator
84 static_assert(std::is_base_of_v<std::forward_iterator_tag,
85                                 bf_iterator<Graph<4>>::iterator_category>);
86 
87 TEST(BreadthFristIteratorTest, MultiPassSafeWithInternalSet) {
88   Graph<4> G;
89   G.AddEdge(0, 1);
90   G.AddEdge(1, 2);
91   G.AddEdge(1, 3);
92 
93   std::array<decltype(G)::NodeType *, 4> NodesFirstPass, NodesSecondPass;
94 
95   auto B = bf_begin(G), E = bf_end(G);
96 
97   std::size_t I = 0;
98   for (auto It = B; It != E; ++It)
99     NodesFirstPass[I++] = *It;
100 
101   I = 0;
102   for (auto It = B; It != E; ++It)
103     NodesSecondPass[I++] = *It;
104 
105   EXPECT_EQ(NodesFirstPass, NodesSecondPass);
106 }
107 
108 } // end namespace llvm
109